Mixed Feelings!!!???? May be long but would love your advice ......

I've been with my fiance for 3 years already. Hes been great , cant say hes a bad guy cause he doesnt cheat, or abuse me or goes out anywhere hes a homebody .. But, I've been losing connection, just because the way he acts when around my family...when we go to my family gatherings he either stays in the car (the whole time I'm there) or in the front yard or leaves early back home. My family has recently questioned me why he doesnt stay or just so distance from them ..... it kinda bugs me , because I feel as if its rude ... he says I never wanna go to his moms house . But when I do I'm there, I'm present, I'm inside talking , not in the front yard or in the car.... another thing is , we can never communicate. If I try to tell him something about how I feel or my opinion .. either I'm wrong or it's all my fault . So I shutdown and start agreeing and stay quiet and listen to what he has to say just so we will stop arguing . I can never get my point across because he talks over me or starts getting loud to the point where my neighbors can hear and as hes being loud hes making me look like the bad one like it's all me... so I shutdown completely. Also, I have 3 kids from my ex...hes been great with them .. but he does sometimes give tough love as he says. There was a time where he would scream at them so much! Until I told him to calm down that they were just kids... he has calm down but theres still stuff that bugs me the way he talks to them ... especially to my son. I'm confused 😏

Yes, he doesnt go out with friends or anything. He works comes straight home to us ... but, as I mentioned the other things .. I just dont know ....