Me and my boyfriend have been together for 2 years (ages 21 and 23). I've only ever met his friends once and that was right at the start of our relationship. His friends have all cheated on their girlfriends, and whenever they're out drinking they lie about where they are and who they're with. I trust my boyfriend but I don't trust his friends. There have been some incidents in the past where my bf has said he got home at one time but turned out he got home a lot later and had lied about where he'd been. I don't have a problem with it but I don't know why he had to lie. The answer I get is that he was so drunk he forgot or that he didn't want to make it worse. I never actually get invited out with his friends but all their girlfriends are usually there with them, I've questioned this but he just says he doesn't know till he's there that they've come.
Whenever he's with them he's a different person, he's quite rude towards me via messages and we end up arguing and not speaking the rest of the night. I don't know if I'm being naive and he's actually a lot more like his friends than I thought or whether they're just bad influences on him and he can't say no.
Does anyone have any advice on how I can deal with it better. I'm not jealous when he sees his friends, I can't really explain how I feel, a mixture of anxiety, worry, etc I think more than anything. I know I should just trust him but every time I do he just does something that makes me question it. Any advice would be great. TIA