“Because they don’t like you”

My boyfriend and I had talked about getting married for a couple years now. And he’s always made up excuses as to why he hasn’t proposed yet.
Tonight I found out the real answer.

His mother and sister don’t like me. To me, they have zero reason to not like me. I’ve always been respectful and helpful, I just also happen to be shy. I’ve never hurt my boyfriend (unlike previous girlfriends). What I think brought this on, is that anytime my boyfriend and I have a fight, he tells them about it. So they’ve formed this horrible picture of me that’s not even remotely true. One of them actually said that they could see me spit in his face during a fight!!! I have never in my life! I would never in my life! That’s like the most disrespectful thing you can do.
Anyways, he and I had a long discussion. But he decided to propose anyways and wants to talk to his family about it next week. Now I’m in an awkward situation because I thought things with me and his family were great, but now that I know the truth, it’s going to be crazy awkward. I don’t want to resent them but I hate what these people think of me.