Would you be ok with her moving in?

So my husband comes from a highly dysfunctional family. He's the only one of his 5 siblings to not end up on drugs, dropping out of high school, being involved in illegal activities and other bad situations.

One of his sister's is trying to get out of an abusive relationship right now. The boyfriend got her hooked on drugs and has been emotionally and physically abusing her for years. She has been clean for about a week and is going to rehab. My husband is going to help her leave the house she lives in with her boyfriend and get her into rehab. All of which is being done in secret to protect her from him. She wants to get clean, go back to school and start sorting out her life. I'm so happy for her! I really want to support her and help her on her road to recovery.

Well she's asked to come live with us when she's out of rehab in 3 months (at least, she could be there longer if things don't go as planned). I am 12 weeks pregnant, only my fiance knows, and I don't think having a recently recovering addict in our home with a baby. I also am really scared of her ex-boyfriend. He put my SIL in the hospital for serious injuries 2 years ago when she tried to leave him once before, he's a dangerous man. I'm afriad he'd come after her and come straight to our home. I don't want to put my unborn child or my husband and I in danger.

My husband and I both think this could be a very bad decision, especially once the baby is born (which would be 3 months after shed get out of rehab). So we're leaning towards putting her up in somewhere else, but close by to us. We'd cover the cost for a few months while she looks for a job of course. But, we're both worried that she'd be more likely to fall back into old ways without a more constant support which has been suggested to us by the professionals at the rehab facility. I don't want that to happen of course, but I feel that my child is more important. I don't want this boyfriend coming within 100 meters of my baby, but I also worry about my SIL using in my home since a high person could seriously harm a baby (I'd never leave my child alone with her of course, but you never know right?).

I guess I'm just conflicted. But, my child comes first right? My husband agrees we need to do what's best for our baby so I don't think she'll end up living with us, but I wanted to hear some other opinions.