Leaving

I’m just confused. A year ago my bf cheated.. and before that he had disloyal tendencies when it came to women. Since then we’ve been in a “Better place”. We communicate more. But also since then I’ve had extreme trust issues. I don’t know when he’s lying or telling the truth because the times I believed he was being honest he was just telling bold face lies. It’s scary. Every now and then we find our selves in arguments, mainly about me over thinking situations... “making it seem like he wants to fuck everyone”... and I really can’t help it at this point. A year later and it’s all still affecting me. I do see his efforts everyday to give me reassurance. But it’s damn near not even enough at this point because idk what to believe. I’m up right now considering leaving. Because I know that this is not how you should feel in a relationship. I just feel bad because in the event that he really has been doing good by me, I would’ve essentially left for “no reason”?? It just seems like a random time to leave when the problems aren’t active. But I can’t shake feeling like this. No amount of reassurance has helped. I just feel like I should be alone for an extremely long time