My (28F) boyfriend (33M) has a female "best friend" (26F) that I don't allow in our house. How should I deal with this?

I've been with my boyfriend for four years, and we've lived together for about two.<br><br>We selected our place carefully, and it's a very good fit for the two of us, but we've never really considered buying or renting together.<br><br>However, his best friend from high school moved back in with her two kids after her husband cheated and they divorced. I've gotten very close to her since she moved back, and I'm pretty sure she'd rather be at our place with her kids than at her husbands.<br><br>I know she's not in love with him, because she told me when we first met. The kids are six and four, and the eldest has a lot of issues, including severe ADHD. She wants to go back to school so she can be home more and take care of them properly. She was very sad and upset when she left our place to go back to her husbands. We've also discussed this several times.<br><br>The kids are a handful, but they're so sweet and loving, and they make me laugh a lot. I'd babysit them if she wanted to go out.<br><br>Her ex-husband is currently trying to get custody of the kids, which is very unfair and upsetting. She has been told that she has a good chance of keeping them, but it will be very difficult, and she's going to need help.<br><br>I love her kids, and I want her to have a good life with her kids.<br><br>However, she has one friend that I don't allow in our house. Her best friend from college. This woman has never met the kids, and she has made it very clear that she hates kids. She also seems very homophobic, which I don't like. She's always making comments about my clothes, and she makes fun of my weight. I don't like this woman.<br><br>My boyfriend also doesn't like her, and he used to be close to her, but she keeps pushing a wedge between them. She says that my boyfriend is trying to steal his best friend away from her, and she keeps sending her nasty messages.<br><br>I don't allow her in our house because she's so mean to me and my boyfriend, and she has no interest in the kids. My boyfriend and I have talked about this extensively, and we're on the same page.<br><br>However, my boyfriend's best friend keeps saying that this woman is important to her, and she wants them in our house together. My boyfriend and I have set some pretty clear boundaries, and I don't think we're being unreasonable.<br><br>How should I deal with this? Should I let her in?