Where should she sleep?

You don't have to tell her dad about it .When i was little ,i had the same situation with your daughter .I didn't sleep alone in my room until 10 years old for i was scared of the dark . Now i am 22 years old and am a university student .It doesm't matter anything .So ,often talk with your daughter and encourage her to be more brave and you can also tell her some stories about sleeping alone that can make her more beautiful or something like that~

My husband has a daughter from a previous relationship and this child would not sleep alone at all. It was a big issue for us. I explained to him that it would be better for her and important for her to learn to sleep on her own. You could let him know how you feel and suggest he bring her back to her own bed and he can comfort her for a few minutes and then return to his own bed. He may have to do this several times a night initially, but it will catch on and she should learn to comfort her own self and fall back asleep at some point. The internet is full of information explaining the benefits of a child learning to sleep on his or her own.

Yes. Maybe he could get her her own pretty bed-side lamp with a low-wattage lightbulb. Failing that, you can get some interesting nightlights now. She has to get used to sleeping on her own.