Welcome to JustAnswer.
You could spend a few months or years in counseling, or I could have you write lists about what he's done and you could burn each one while saying goodbye to it... or you could just cut right to the chase. I suspect you jsut want to cut right to the chase.
The botXXXXX XXXXXne, is that you make a decision (1) to get over what that guy did NOW, and (2) start your new life trusting new people until they give you a reason not to trust.
Next time he shows up - just explain to him that the two of you have gone around and around - and can't make it work. Tell him it's time to move on. Tell him it's over and there is no going back. If he needs it - tell him that love doesn't make it work.
Then move on without him. Do whatever it takes to start a new life. Choose only to be around people who exhibit personal integrity - don't stand for less.
Learn about trustworthiness; what are the signs that show someone is trustworthy - if people display anything but those things, or show you they are liars, or cheats, or jerks to their ex's ... move on right then and there. You don't need people to show you over and over for 3.5 years - they can show you once or twice and that should be it - you then move on from them.
And finally - if you don't know how to find a better type of person - go to a matchmaking service that does it for you. There are some in every town and some online.
Don't settle - be with people who are worth your time.