Is it normal to not have sex/be in a relationship for 5 years?

Ever since an ex and I broke up 5 years ago I haven’t wanted to be with anyone else. I feel like I could never love them as much as I loved him, I would just compare them and it wouldn’t matter. He and I dated for 3 years, friends for 8. Our relationship was really rocky towards the end, he constantly lied about things such as where he was and who he was with. I eventually found out he was cheating on me with his best friend. Even though he had cheated on me I was still willing to be with him if he stopped but he confessed that he always had feelings for her and wanted to be with her. We broke up after that and they’ve been together since. Recently they got married and she’s pregnant with their second child. I still keep track because even thought he has destroyed me a part of me still wants to know how he’s doing. Of course I don’t want to get together with him ever again, I am happy for him I know he cares about her a lot. It just hurts knowing that could have been me. So now I’m stuck in the mindset that everyone I encounter will hurt me the way he has.
I should be over it, it has been 5 years but I can’t seem to move on my fears are too strong.
I honestly want to try to be with someone again but I’m scared of having my heart broken again, I don’t know what to do at this point.