He jokes about having other bitches

My boyfriend and I have a dark sense of humor. It’s funny at times but other times he goes to far and I get mad which causes an argument. He then ends up calling me crazy

For ex: he would say don’t leave anything in my car I don’t want the other girl to see it

Or he says things like I’m only with you because your pussy is really good. That causes me to think he’s cheating on me and a lot of comments like that now have me thinking he really is cheating. When we speak seriously he swears he never has but idk.

Another issue is he’s so stingy with me and I always go out for him. Today is his bday and I got him car parts. He’s never gotten shit for me…