Thanksgivign drama

Been with my bf for over 3 years and been living together for 2. He pays half of the rent and I pay all of the bills & 1/2 of the rent. I’m ok with that, but I tell him i feel weird supporting a boy that’s not my husband yet. Well it is what it is and here we are so I can’t change that right now. I’m in school right now for over 20 hours a week & I work full time as well over night shift. He does the dishes, takes out trash , etc. he’s pretty helpful around the house and I always thank him for helping around. Well we have had our ups & downs. Me and his mother had a strained relationship because she’s just overall a b*** in my opinion & doesn’t like me but fakes it (Long story) & she’s always on social media but never likes any posts that he or I post together. She only likes some posts he posts on his own. Anyways, one thing about my bf I hate is that whenever I want to open up to him about his family he always says he doesn’t want to hear it and. For example. His cousin was hired to build on my families second home. But instead, his workers drank beer all day & stole from my family. My parents fired him and he had a fit and demanded money from her anyways for wasting his time. I told him about it and he said he didn’t want to be bothered about it and doesn’t want to talk about it. It’s like he hates when you talk about his family. This happened 4 months ago & I’ve just let it go. Well thanksgiving is coming up and the whole family will be there & his cousin. I told him I don’t wanna go but didn’t tell him why. I haven’t seen his cousin since before the incident happened at my family’s house. I then finally opened up and told him I don’t want his cousin to say anything to me about what happened because his cousin is an asshole and he just says whatever is on his mind. I told him that’s why I don’t want to go because I don’t want this issue brought up but knowing is cousin, he will bring it up again. My bf said again that he doesn’t want to be bothered and he doesn’t want to talk about it and why am I bringing it up again. I got upset and I’m just really fed up at the moment. Why be in a relationship if we can communicate like fking adults?! Am I wrong for feeling this way?