Confused

I am in a relationship of 10 years I have been faithful every way possible. In the last 10 years I have been accused of cheating(understandably given he doesn’t know whether his oldest is his or not) ex’s a. I’ve been cheated done this before with my biological oldest father. I’m thinking I maybe to trusting of my SO atm. He used my best mate 4 years ago and tried to cheat. He now is either way to needy or accuses me of cheating again. Fuck me if life was that easy!! We have done a lot over the years I’m just wanting options on how people would feel on s**t like this. It may help.