APPROPRIATE TIME TO STOP: whenever you and/or husband and/or kids are ready.
IF KIDS ARE CRAWLING INTO YOUR BED AND YOU HATE IT: Then quietly (no words) take them by the hand, walk them to their bedroom and climb in their twin. They are afraid. They just want to cuddle (I love to cuddle) and EVERYONE values sleep. So sleep. I don't mind my 8.5 yr old coming to my bed. And trust me, if I'm too dead tired, I just say come in. But I will usually go to her bed so she * knows * her bed is safe and the best place to sleep in. Put positive associations with nighttime sleep. Her bed is a GREAT place to sleep and when she needs you, you'll go there.
HOW TO DO IT: If you want them out of your bed and bedroom (which I think is the best thing here) you need to set up twin mattresses in their rooms. I transitioned my son to his own twin mattress/bedroom when he was 2. (DH insisted. I wasn't happy about it at the time, but it was the right call.) From now on, all sleep happens in THEIR room, so they get used to it. What would help with this transition is you STILL co-sleeping with them (and slowly weaning that off) in their rooms.
My daughter was born when my son was 4. She co-slept with DH & I for about a year and then I started putting her to sleep (nursing her to sleep) on the twin mattress (pulled out from under my son's twin) next to my son. I had a barrier up so he never fell on her the first year because I was nervous. He remembers liking having her in his bedroom because it helped him feel less afraid.
When I'd nurse my daughter to sleep, he'd come down and cuddle with us. Eventually he got sick of that (too crowded on a twin) and on his own went to sleep on his own bed.
I used to cuddle my son to sleep and then sneak away. If he woke up (and he always did - around 2am) looking for me, I'd never invite him to our bed. I'd go to his room and stay in his bed.
My son eventually started sleeping through the night.
My daughter was always a solid sleeper. But when she used to wake up at 5am, walking across the house to our bedroom, I'd get up and lie back with her. No arguing, no fights.
I still lie with my 8.5 yr old daughter (I wish I didn't have to) to get her to relax to sleep.
I gave them each separate bedrooms the summer before she entered Kindergarden. I knew she'd have playdates and I didn't want my son feel like he was being invaded by strange kids he didn't know.
MARRIAGE: I don't know what's going on in your marriage. But, I'd recommend looking into this. People have said they were on the brink of divorced and after attending this, things change.
http://newlife.com/newlifemarriageweekend
They have a call in radio show and give excellent advice. You can listen to previous podcasts to hear what it's like.
This is another one, similar concept:
http://www.familylife.com/events/featured-events/weekend-...
I would love to attend one of these one day. I think everyone (from blah marriages to horrible marriages) can use a tune up.
Nobody's marriage is perfect. People struggle. I think there is help. Don't give up on it without getting help first.
PS I think this is more common (co-sleeping AND marital problems BTW) than you think. With co-sleeping, a lot of people end up doing some combination (not in infancy, maybe later) and struggle also. You are definitely not alone. :)