Damn it! I Hate Deja Vu sometimes!

I feel like I've been down this road before and I really hate how things went.  I've become involved with a female friend.  She has a boyfriend.  I know my role and stay in my place.  We had a conversation yesterday which alarmed me.  She told me that she "gave in" to him and then had sex. I have no problem with that.  They are both consenting adults.  My problem came up when she said he got rough with her.  She didn't go into details but I'm sure she will eventually.  I'm not a fan of any male who puts his hands on a female when she does not ask for it.  I'm not a fan of guys who sweet talk women into sexual acts they are uncomfortable with.  This scenario happened before and I really don't want to see a sequel.