In their own rooms. You are supposed to be his intimate partner yet he wants you kicked out of your joint bedroom into the kids bedroom while they sleep in master bedroom with daddy. What does that say to his kids?

That you are beneath them in importance and it doesn't model appropriate relationship behaviours. This deal will kill any romance and you will start resenting him.

my husband is very clear even on holidays that his kids from exwife are not permitted in our bedroom, that is my personal private space and the place we are frequently intimate together and he will not allow his kids from exwife to interfere in those private boundaries.

you need to make it clear to this man that you will not be moving in with him as his intimate partner only to be kicked out to a kiddy bedroom whilst he cosleeps with his 6 & 8 yr old daughter and son. There are plenty of men out there that wouldn't stupidly make this a term of moving in together. 
 

the only kids who should sleep in that room is a baby of that relationship or minor kids and i mean toddlers if there is space. Kids not part of that relationship need to understand daddy has a partner or spouse now and they share this private room with their intimate partner or spouse.

this man needs to be actively training his kids to sleep in their own room or when they're sick and then move to your bedroom once kids fall asleep. It's unacceptable you be sleeping separately half the week. Why bother getting into an intimate relationship or move in together??

My SD cosleep until 10. Neither DH or BM would do anything about it. It finally ended when BM got remarried.

Obviously I wasn't going to do anything but I didn't want SD to think that it was okay to sleep in a bed with a parent and an unrelated adult.

If my DH was going to co-sleep he would do it in SD's room with her not kick me out of our bed.

When I met my DH 23 years ago, his 3 children (aged SD3, SS5 and SD9) co-slept with both parents).  I informed my DH at that time," I don't sleep with children", which seemed like a reasonable statement from a non-related adult.   That ended that issue, although it took a year to get them to quit banging on the closed bedroom door to get them to stay in their own beds.  I almost lost my mind during that first year, given that I had a high stress job and was being woken up at least 3 times a night.   BM continued to cosleep with them well into their teen years, which has caused huge issues in their lives to this day.  So sleeping with children says more about your boyfriends needs and less about yours and the childrens needs.  I'm not sure why these parents are so against their children growing up and gaining some level of independence.

for a partner. I don't think I'd even address this issue. I'd just tell him we aren't compatiable. Or, if you must....let him know why but don't let him gas light you into staying in that mess. 

No way a grown man doesn't realize what he's doing and saying when he tellls YOU, his partner, that YOU will leave HIS bed so his KIDS can sleep with him. He knows and he's clearly showing you the future with him. A life of hell. I say, run like hell. Just go read a few posts on this board and see what kind of behavior your partner is instilling in his kids. Behaviors that will negatively impact you for the rest of your life, should you choose to couple with this man.

This would not be the relationship for me.

is saying for half the week he has them I would have to sleep in one of the children's unslept in beds as there is just not enough room for us all.

I mean, he told you where you stand.

relationship bed so he can co-sleep with children.

His children or not, there is only one answer IMHO.

Oh hell no!

I'm hoping someone can post the signs of the Disneyland Dad. I can't seem to find it. Anyway, I'm a veteran SM with the battle scars and YEARS of therapy to show for it. My SKs were infantilized and overly coddled just like your potential SO's kids. Another very important thing to keep in mind is to not make the mistake of counting down to 18. Coddled SKs do not meet milestones when their peers do. They don't get boyfriends/girlfriends when their peers do, if ever, so you can't count on them being out of the house and not rammed up Daddy's ass all the damn time. They don't move out, and you can quote me on that, and they don't drive when their peers do. You might want to find the Disneyland Dad signs on here or really read up on Steptalk because the co-sleeping and still wiping the kids' asses is only a symptom of an issue that has a very poor prognosis. In my experience, my DH fought tooth and nail to keep my SKs as helpless infants. Families like this have attachment issues and other kinds of issues that cause the parents to create the dynamic. Dads like my DH and likely your SO will sabotage any sign of healing or evolvement to knock things back into status quo. The onus will be put on you to suck it up and give up on having your needs met as a spouse. Also, given that your SKs are overly coddled and one of them is a girl, you will face Mini-Wife Syndrome. You will come dead last to a female child and believe me there is nothing more painful. If you say one word you'll be labelled as the "jealous SM" or mean or whatever other negative term there is for a SM. 

You made the right decision, for yourself and your kids. Imagine how confusing all of that would be to them. You're showing them strength and independence. 

His response of "don't talk about my kids like that" would be a dealbreaker for me. My DH had a few of the DD traits and we went through some growing pains but he was usually improving rather than regressing in his parenting and boundaries. It still isn't perfect but overall I get my needs met and am treated well by my partner so it balances out. Someone who won't even allow you to talk about it? That guy has no growth potential. Coming in after the kids and the kids dog is no way to live. (BM tried to bum off the dog she irresponsibly got for YSD on us. The dog has severe behavior and anxiety issues from being raised by nutjob BM. DH said NO, I bet your custard puff guy would say YES without even asking you.)

Yay for you and rejecting an unhealthy situation/lifestyle for you and your kids.  Yeah it hurts but not anything near as 10,20+ years of this lifestyle!   Don't allow yourself to wallow for too long.  This is a good thing and another frog off the list.  

dhildren. Buh0bye"

End of relationship, end of problem.

You are not selfish. He is .... stunted.