The man in my life was cheated on by both of his ex wives... and he hates it whenever
I talk with male friends/ co-workers... or, any male for that matter. He even caused a scene in a restaurant because a man... who I didn't even know... smiled and said, "hi" to me. So, your boyfriend's distrust could be from his own past personal experience. But, this behavior makes you feel like you're being marginalized, squeezed and constantly scrutinized. That's what Jealousy and Distrust does. It instills insecurities which migrate into relationships and subsequently places a strain on those relationships. If things continue to spiral out of control... you may have to re-evaluate if there's a future with him.
You have been dating a long time for him to still have these insecurities. Trying to control another to stay close to them is a trap that many fall into. He feels threatened for some reason by your friends for some reason. Is he friends with your pals too? That is often a great way to weed out issues. If he is brought into the mix as a friend as well particularly with any male friends, he might feel better. My husband had a gaggle of female friends when we got together. Some were just friends and they remain today. Some had a crush on him or something was amiss and those friendships went by the wayside. Why? Because I was on the scene and those with less than desirable intentions as far as I was concerned backed off. These weren't women that he would have dated but women that liked him in that way anyway. Ya know what I am talking about? And I tell ya, I could spot them a mile away. I'm not insecure. I'm just perceptive.
So, I don't know if any of that is going on but by bringing your boyfriend into the mix, he may feel less threatened.
If he is already there, I'd ask him point blank why he is thinking you'll cheat. If you don't like the answer to that, then I think you'll have to consider your options here. Relationships are about trust and if he just can't trust you and tries to control you, that gets worse over time. It is not a good way to live. Good luck!
I always think if someone is accusing someone of cheating it's because they are guilty of it themselves. If he isn't than he's just very controlling and insecure. If he has no trust for you or your relationship than you really don't have much of a relationship. You should express to him that his behavior is pushing you away and if he can't get a handle on it then I don't think you have much choice. You either stay and put up with it and give up your friends for him or stay arguing with someone every day, or you can leave him. The problem is not yours.