I have some insight on this. My boyfriend lied to me about other girls and I caught those lies on my own. Only when I caught him was when he admitted to them, so there’s a whole bunch of other lies I don’t know about bc I chose to stop digging. There has been no trust gained back and no reassurance. I find that whenever it bugs me or comes across my mind, or just really ruins my mood thinking back to those times and I try to talk to him about it. He dismisses me, tells me I have trust issues, and that I’m stuck in the past. I’ve learned that they do this because they don’t want to own up to the wrong they did. They would rather coward away and gaslight you to make themselves feel better about their mistakes. I say don’t lose yourself in trying to find reassurance or validation through him. Do everything in your power to now be codependent either. It so easy to get stuck in a cycle like this, but if he doesn’t serve you and gives you what you need to feel happy and secure...then I think you have to reconsider the relationship. Looks like if you were to try to even talk about this to him, he will brush it off too. But it’s also worth a shot if you really want to be with him.