That's plain inappropriate, to begin with. To make matters worse, once you move in together with BF and she loses her place in bed, she'll resent you, as you're the cause she doesn't share the bed with Daddy anymore.
Honestly, either you talk to your BF and he puts an end to that situation right now or maybe you'd better consider moving on to another BF. Sorry...

I couldn't stay with a man who would co sleep with a 12 year old. I understand she's his daughter, etc. But I still think it's wrong. And it would definitely cause problems in any relationship he has if she had to stop after a certain length of time because she's probably used to it now.

You wrote he shares the bed from "time to time". So I am assuming here that this co-sleeping arrangement isn't definite.

I had a similar problem with DW and SS. My Aunty Jo slept with my cousin up until his teen years and the circumstances were similar to your boyfriend's. Aunty Jo's husband (Uncle Pete) passed away and Aunty Jo basically latched onto her son for emotional support.

So my first question to your husband is "Is this sleeping arrangement just done for the sake of convenience or is it something else?"

I sometimes lay down with my son and my daughter (they are 3 and 5) but I will not sleep with them. They recenly changed bedrooms and they are still trying to get used to their new sleeping environment. The reason why I am against co-sleeping is because I have seen first hand the damage it causes. The longer you take to ween your child off of co-sleeping the harder it gets. My SS is 15 and he still has trouble sleeping at night. He is the only one who will call out for his mother in the middle of the night because he saw a bug or something.

So talk to your husband. The longer he takes to ween his daughter out of co-sleeping the harder it will get.

Any parent who sleeps with a child going through puberty gets my eyebrows raised at that behavior.

But even if it was totally appropriate, you are setting yourself up for a lot of drama from a girl who is well on her way to being a mini-wife. Google mini wife syndrome

What tommar and Miss K said, especially.

Bottom line is you can't "correct" it, really. Because it's about an entire mindset that is not compatible with yours. Don't "move forward" with this guy, he is NOT the guy for you.

Being a widow, I understand it at the beginning. When she was 6!
I was selfish and wanted my kids close to me.They were very young and even then they wanted their own bed. I told my friend about it. She laughed and said I would be grateful at the end and my new lover would appreciate it, too.
Your boyfriend wasn't lucky enough to have such a friend.
Old habits die hard. Let him know it gives him a creeper status! Good luck!!

Kid/parental co-sleeping on a regular basis is not something I am supportive of at any age. A 12yo and a parent, regardless of gender, is completely inappropriate IMHO.

Ask him when he began having wet dreams and started playing with Mr. Happy as an adolescent? It was probably when he was about 12. His daughter is probably experiencing the same adolescent stage currently.

Time to let her snuggle with a stuffed animal daddy, to avoid any issues. If he can't see it then he is not intelligent enough to invest any more of your time in. Even with the tragic loss of his former DW and SD's loss of her mother this is not right.

As a man the idea of co sleeping with a 12yo girl is a repugnant thought as I think it should be for any man. No less than would be the case co sleeping with a 12yo little boy either. If this is even a remotely regular thing it is just wrong.

That is my worst nightmare! Seriously, I could not handle seeing my SD14 in my bed. I would lose it.

I discovered ths crap when I started dating SO. Apparently, SD (11 at the time) had ALWAYS had problems sleeping and SO would lay with her from the age of 5yrs old. After BM took off, she would scream for dadddeeeeeee and he would go to her.. this set a horrible pattern.

She was 11 when SO and I started dating and the first weekend I spent there freaked me out. Her bedroom is right next to SO's and at about 11pm we heard her crying. SO leapt up out of bed and tore into her room..and stayed there until nearly morning. To say I was freaked out, was an understatement. I googled..found this site and did some reading. I told him he was setting a dangerous precedent as she was maturing and he needed to stop letting her come to sleep in his bed (which she would do if he didn't go to her).

I told him about "emotional incest". Needless to say, he went batshit and we had a massive blow up. We went to counselling and this was when the Counsellor explained to him why it was such an awful idea. He never did it again and never allowed her into his bed again after that. It took a professional to let him see that she wasn't "5 years old" any more and had to be treated as a pre-teen.

It sucks and I recommend counselling for him to wake up and see the light.