I just married a woman with a 4 year old son.  She has been a single
mother to-date, and I think some of her son's behavior reflects that. 
Most of it we are able to work through, but one particular behavior
has been persistent, difficult to deal with, and is beginning to
concern me in regards to his overall development.

For the past 4 years, and his entire life, her son has slept every
night in the same bed as his mother.  He has always fallen asleep and
woken up next to her.  After getting married and moving in together,
we gave him his own room with his own bed and tried to ease him out of
this pattern.  She would literally lay next to him in his little bed
until he fell asleep.  Then she began sitting next to him and stroking
his head until he fell asleep.  This seemed like forward progress and
he seemed to be sleeping through the night as he did not enter our
bedroom, although he would wake at the crack of dawn to come into our
room and mess with us in bed.

However, in the past two weeks, our forward progress seems to have
halted and we are even going backwards.  He is now waking up at random
times during the night and sneaking into bed with us.  If we take him
back to his room, he'll oftentimes wake up and come back.  When he
wakes up at the crack of dawn, he comes into our room and goes to
sleep in our bed next to us.

In talking to him, he's not scared of anything in his room.  He simply
wants "mommy to lay down with him".  He'll repeat this over and over.

I new to fatherhood and parenting, but I think at his age he should be
able to sleep by himself.  I understand the circumstances he is coming
from, and so I am well aware that a gradual approach is necessary, but
it seems to no longer be working.

How do we get him to sleep by himself after a lifetime of sleeping with his mother?

When my younger daughter was of a similar age, she often came into our
bedroom in the middle of the night and then just stood near the head
of our bed.

It rarely affected me because I sleep soundly but it used to freak out
my wife who took the little so-and-so back to her own bed.

We didn't do anything special and eventually she just grew out of it.

I guess your 4-year-old will also sort himself out in due course when
he realises that he's wasting his time.

All the Best

Bryan

[NOTE that the text below was inadvertently posted as an answer, and
is being/has been removed]

cseta-ga, 

You asked:  "How do we get him to sleep by himself after a lifetime of
sleeping with his mother?", but it sounds like you've already
accomplished this.  The little tyke IS getting to sleep on his own,
but is also waking up in the middle of the night and crawling into
mommy's (and your) bed.

Geting his to even go to sleep on his own is a big step, and is a lot of progress.

From my perspective as a father of two boys, none of this sounds too unusual.  

Getting children (even a 4 year old) to sleep on their own is tricky. 
Some backsliding always seems to occur when kids are asked to take on
new challenges, like the two of you are asking of your child.  And
nowhere is the challenge of adjustment greater than when a child is
thrust into a new and uncertain situation, as your son now finds
himself, with a new dad at home.

As frustrating as the middle-of-the night interruptions are, it sounds
as if you and your wife (congrats, by the way) have made progress with
your son already, and are doing things the right way (if there can be
said to be a 'right way' in parenting...if there is, it's hard to pin
down).

You both have a common goal of getting your son to sleep more
independently, and you're both being fairly consistent, it seems, in
encouraging the kid to make the adjustment.  I have no doubt he will
continue to make progress over the next weeks and months.  Somehow,
all kids wind up sleeping on their own after a while.

Today, he wakes you up at the crack of dawn.  Tomorrow, he'll be
coming home at the crack of dawn after being out all night with his
buddies.

Enjoy his four-year-oldness while you can.


pafalafa-ga

Get him a big stuffed toy he can cuddle with at night.  Also, a lock
for your bedroom door would help.

Sleep in his room for a few days

- either his mother will sort him out, or you need to be out of there

(the female is deadlier than the male)

I wouldn't lock the door, but like someone I know with young kids put
a door knocker on the door, down at his height, and teach him to use
it always, day or night, before entering your bedroom  - and to wait
for permission to enter.

He should like having his very own door knocker.  Mom can practice
with him during the day, calling him to her and reminding him to
knock, and if he doesn't, asking him to close the door again and knock
first and to wait for her "come in".

Not only will he learn to respect the privacy of bedrooms in general,
if he still comes in without knocking, reminding him that he must,
will distract from his immediate intention of joining you in bed, and
will also allow you to ask him to or to lead him back to his bed
before he can creep under the covers.
(Might help if the door creaks or the latch is loud, if that can be arranged.)
This seemed to work in the other family.

Nelson! Oh my goodness, don't lock your door! That's horrible!

It's very normal behavior. Sleep issues are probably one of the main
topics that parents bring up with pediatricians. For that reason,
famed pediatrician, Dr. William Sears (I *love* his books and his
approach) has written a book specifically about sleep issues. Here is
a link to his "Sleep Problems FAQ":
http://www.askdrsears.com/html/7/T071100.asp

Also, in many cultures, it's quite normal for families to share beds
for many years. Some believe that it's the "independent, American way"
to encourage especially children to sleep in their own beds and in
their own rooms. Look at all of this information on "the family bed":
://www.google.com/search?q=family+bed&sourceid=mozilla-search&start=0&start=0&ie=utf-8&oe=utf-8

Enjoy your marriage. Enjoy your child. Enjoy the cuddles. 

A nice transition that we use with our children is "the special bed."
I know you've said your son isn't doing it because he's scared, but
this may still interest you. Yep, it's another Dr. Sears technique.
http://64.233.161.104/search?q=cache:mfsMSF62IxAJ:www.iparenting.com/sears/answers/nightmares.htm+dr.+sears+special+bed&hl=en&gl=us&ct=clnk&cd=5

I hope that helps! I know it can be frustrating at times and you are
in a very new situation yourself. It sounds like you all have a pretty
decent handle on things overall and are acting responsibly and with
care. I hope you find this information helpful!

Sincerely,
Boquinha-ga

A couple more resources for you:

It doesn't seem to have the best reviews on Amazon, but Dr. Sears has
a book all about sleep issues. He encourages co-sleeping and explains
how that actually fosters independence more than forcing a child to
cry it out and sleep alone. It makes sense to me.
http://www.amazon.com/gp/product/0316776203/104-3348376-7132725?n=283155

I'm amazed at the negative Amazon reviews, but here is the book that
got us into Dr. Sears' ways. We really like his gentle, loving
approach. It resonates with us. You've got to pick what works for you
and what fits well with your family.
http://www.amazon.com/-Discipline-Book-How-/dp/0316779032/ref=pd_sim_b_4/104-3348376-7132725?ie=UTF8

I don't suppose there is any point in suggesting you lock his door at night.
Or you could tie his feet to the bed post this might work.

My patents did this to me and it didn't not do me no harm

Kemlo

I'm interested in hearing an official answer when it comes. A friend's
husband was away for work for about six months and during that time,
their son started sleeping in the bed with her (he had never done that
previously). He's 3 when this started but now is 4. I thought she was
making a mistake, and even since his dad returned the child wants to
be in bed with Mom at night and sleeps with both of them. She was
opening up a can of worms that will be very hard to close, I'm afraid.

Although controversial, I like Supernanny's techniques:

Rules for Bedtime 
http://www.oprah.com/relationships/relationships_content.jhtml?contentId=con_20050121_bedtime.xml&section=Family&subsection=Parenting

Supernanny's Techniques (general)
http://umibrahim.tripod.com/id13.html

It seems likely to me that he's having nightmares.  When you said he
was waking up at random times in the night, that tipped it off --
something has to be causing that.

I went through a horrible period of nightmares myself around that age.
 Why don't you ask him if he's having lots of bad dreams lately?

Have  you tried a reward chart?  This has worked well for my son. 
Each day that he has stayed in his bed all night long, he gets a
sticker on a chart.  Once he gets so many stickers, he gets something
special.  It doesn't  have to be anything expensive, a special snuggle
time with Mommy in the morning, a matchbox car, or something like
that.  Kids like to look forward to getting something and they like to
look forward to accomplishing something.

Also, be consistent.  I know it's hard when you want your sleep too,
but if he gets into your bed in the night, give him a chance to go
back to bed on his own to earn a sticker, and if he doesn't, bring him
back to his bed.

Make sure he feels comfortable and safe in his bed.  A nightlight
might help.  A favorite stuffed animal or toy nearby, or soft music
might help too.

The reward chart can be very simple.  A piece of paper with 3 circles
on it.  He puts a sticker on a circle each time he sleeps in his bed
all night.  When it's complete, there's a reward of some sort.  You
can start with just three circles, then 5, then 10 circles.  When
sleeping in his own bed becomes routine, you can stop using the
charts.

My son was waking up in the middle of the night to snuggle with Mommy
just because he could, not because of nightmares, so I suspect that's
what's going on. But, do ask if he is scared just to make sure.

The chart worked very well for us.  We sleep a lot better now.

I had the same situation with my daughter. I had been a single mom and
she had always slept with me, then i met my husband, and she still
wanted to sleep with me. she would come in at any hour during the
night and just crawl in bed.
what we did was a reward chart. If she didn't come in my room during
the night she would put a sticker on her chart, after a week of
stickers she would get a prize. ( I had a bag full of differents
things she liked and she could pick what she wanted.) after 4 weeks
were full of stickers she got a big prize, I think we took her to a
fun place that had go-carts, mini golf, video games etc...
I worked after just 4 weeks, she is now 9 and has been sleeping in her
bed for the last 5 years! We are now having this issue with her
younger brother who will be 4 in a month. He has never slept with us,
but for some reason now gets up 3x a night and gets in our bed.

Hope this helps.  Good Luck!

Esta blishing a bedtime ritual, making it fun but "firm" works. I
found a lot of help about how to do this here 
http://www.familiesonlinemagazine.com/kid-sleep.html