Intimacy and affection is key in your case I think. You don't need to go overboard. Go to him after a long day and say '' I had a crap day today'' and snuggle up to him. Feeling like we are needed can do wonders on a man's ego and self-confidence ;)
This sounds like an anxiety issue. I myself, suffer from anxiety. Suffers always find something to worry about and for me, the stress is always centered around my relationships. If you care about this guy, be supportive and consistent, no matter how many times you have to say it, tell him again and again how much you care for him, and that he is the only one you do care about. If he is like this about any other areas in his life, I can almost guarantee his anxiety is being misdiagnosed as insecurity. Sounds like you already care enough about him just by asking for help. You're on the right track for sure.
Lots of girls nowadays are really promicues lol. One day she says she loves you the next she is blowing aome hilibilly in some alleyway. Guys, donot trust hoes. Screw them and then pass them along lmfao.
it's almost impossible, i had a girlfriend like your boyfriend, she was extremely paranoid, always thinking i was hooking up or texting with other girls, while i wasn't. I tried to explain her several times, that im not that type of a person and that i really like her. It really didn't make any difference. I tried for weeks untill i had enough of her insults, her insecurities and all her false promises. So when i told her she wouldn't see herself how wrong she was, and i haven't talked to her since. I have a new girlfriend and i really like her, i can be myself with her and thats the most important thing to me. With your boyfriend, maybe have a serious conversation with him, on how you sometimes perceive him, and if you are wrong for thinking like that, if not, he should speak out. A relationship isn't always about fun, its also about discussing serious matters with each other.