please give me advice

I'm sorry if this comes off as rude I don't mean to but. My bfs mom is very nice and all. She expects a lot from my bf and when she says something he has to do it. He is 20 so he's not a child but he has to listen to her which I understand. For example if she wants him home when he's with me she gets her way even though she has no reason besides wanting him home; even tho he lives there and he planned to have dinner with me which she knew. Well lately every time she invites me to come with his family my bf goes "my mom said you have to". I'm 20 and barely listen to my own parents let alone need someone else to claim I have to be there. I understand she's being polite and all but I wish they didn't come off so hard. Can anyone relate. I just don't want this problem to continue to grow.