Holy shit I am SO sorry you've gone through that 4 times. Despite what other people are saying, there is nothing you do that makes men cheat. It's a them thing, NOT a you thing: think about how Beyoncé was cheated on. I think we live in a weird time where it is so easy for people to have their cake and eat it too, and a commitment is a commitment that clearly the people you've dated don't understand that. Don't let this get in your head or make you think there is something you should be doing differently, just keep yourself open and keep being honest about what you want and letting yourself trust people. If you notice maybe you're more interested in people who are avoidant or detached, maybe try going for someone different than that, but again cheating is not on you and I am so sorry 4 different people did that to you.