Okay need help ASAP

Okay my boyfriend and I have been dating for six months we got serious pretty quickly and everything has been great.

Well he has the sweetest daughter in the world and this is the first time I’ve dated someone with a child. I know that with a child involved the mother is always going to be involved in his life I understand that and been understanding about everything. Except for tonight this one I don’t know how to feel about.

Some how he got roped into going to dinner with his ex wife and her family. Now we have talked about how he wants things to be civil for his daughter sake and I want that too very much I want to get along with her and be civil.

But dinner with her and her family I just don’t know how to deal with that. My last two relationships I was cheated on so I’m struggling with this one