Relationship issues

Me and my SO have been together for almost year and a half and he used to want to have sex all the time (he lost his vcard to me) and now well have it once or twice a month. He says that its his parents house and doesn't want to disrespect it or he's too "tired". We're both in our early 20s and in college. So we're not kids. Another thing is that he always makes comments that make me really mad, for example yesterday we were about to have sex and there was no foreplay and practically had to beg for it and when he put it in it hurt cause I was not wet enough and I told him and he said "goddamit wtf?" Like that's so rude. We were also watching a movie and 50/50 and in the movie the guy burns a painting that the ex made him. And then he told me that he would do burn a card I made him if we broke up. Like why do I have to know that? Its hurtful. So I started crying cause the card I made him took me like 2 hours and I made it with lots of love and he always says oh "I'm sorry I'm going to change". Yet, in my part I sometimes feel like I'm the abuser because I have jealousy issues where I get really jealous if he dresses nice for work or talks to other girls or when he goes to places without me and I go thru his phone. Another thing is that the reason why I am so untrustful is because when we first started dating he told me that he wanted to experience other girls and decided to stay with me. And he has told me that I need to lose weight several times and I do I know I do but its hard with PCOS. But yeah a idk I just want to know what people thibk? Sometimes I want to just end it but then things get a little better.