I think this is more of an inconvenience than a problem. I used to let my BD's sleep with me from time to time when EX was working graveyard. They loved it and so did I.

I confess...I did the exact same thing...sharing my bed, I mean. My daughter and I were on our own by the time she was two. exH was in the military and lived states away...and didn't really stay in touch with DD for many years. Right after we got our own place, DD got very ill and I took her into my bed one night to keep an eye on her. She didn't leave my bed for years. She had her own room with a brand new bed and new comforter set. I bought many sets of sheets and throw blankets and even two new comforter sets trying to get her in to her own bed. The only way I got her into her bed was when I moved her bed into my room. Then, when we moved into our house, she was back in my bed...new place was scary to her. About a year and a half ago, I finally got her into her own bedroom...she is almost 14 years old. BUT...it's just the two of us in our house (we don't live in the same house with DH and skids), so it doesn't affect my marriage bed. Every once in a great while...she still wants to sleep with me, but even those are getting further and further between.

I am not saying this is the best way for everyone, but I think my daughter and I have a pretty wonderful relationship because of it. Many nights of talking until we fell asleep, tickle fights, back scratches, all wonderful things, there is a closeness between us that I am not sure would be there if I hadn't allowed her to sleep with me. Matter of fact...when she finally went to her own room...it took some getting used to (having the bed all to myself!) and at first, I got up two and three times a night to make sure she was ok. I consider my daughter a well rounded kid, fairly well mannered (when her teen attitude isn't messing her up!), great grades in school, makes good friends and is good to people around her. So...I don't see a problem with it. But...this is just how it worked for us....

Sounds like your BM is basically ingraining in your SD that she can't sleep alone and that's a hard habit to break. We try really hard to keep DS in his own bed - he recently started getting up and crawling into our bed. The sad thing is that I almost never notice until I almost roll over on him when DH is working nights. If we're both home, he has to crawl over one of us and it's usually me. I don't have an issue with it from time to time but not every night. I'm working really hard on the weeks when my DH is on days that he not go in an lay down with DS until he goes to sleep - makes life really hard when DH is not home and working nights and I'm trying to get DS to bed while dealing with DD who is 8 weeks old and has colic.
Try as hard as you can to just gently get her back to her bed and be firm about not taking on behaviors you are uncomfortable with.

We co-sleep too. The thing about it is the kids like the security and comfort of it. Hey like cuddling next to a warm body to fall asleep. You do it, too, right? You like sleeping next to a warm body because it is comforting or whatever. It's the same with the kids. So instead of having bf just demand that she sleep in her bed alone, have him lay next to her til she falls asleep. He can read her a story, sing her a song, pat her back...whatever she needs/likes to go to sleep. When she's asleep hen he can leave. Of course it will take time and effort on his part so if he isn't willing to help, then....