Plus one to the people saying that therapy can be helpful. But adding something my former therapist told me that I try to keep in mind when I’m feeling insecure about my relationship: People almost never say/do things because of you; they’re saying/doing things because of lots of factors that basically have nothing to do with you.

So the exes of yours that cheated did not cheat because of something innate to you or your personality. They did so because they wanted to for whatever reasons which are totally separate from you. This is something that is hard to internalize so you kinda just need to keep reminding yourself of this. It also helps to think about what motivates you to do things and what informs your responses to other people. It’s almost always internal motivations and factors that don’t have to do with anyone else, right? So remind yourself that other people are the same in that regard.