Boyfriends anxiety


So my boyfriend has been cheated on in every relationship he’s been in. Due to that he has a hard time with his anxiety in our relationship. He gets upset when he knows I’ll be leaving for long periods of time because he’s not used to his girlfriend coming back and he gets upset when I mention myself hanging with a male friend or coworker even though we have discussed before that we need to be able to trust eachother with the opposite sex. He has been trying to work on the anxiety and he knows I would never leave or cheat on him. I was wondering if anyone knows any ways I can help him with his anxiety and help him understand I would never hurt him