It’s great that you’re realizing what caused this dent in your self esteem. Yeah, I am starting to think, things like stuttering, are our bodies trying to tell us something isn’t right. Rather in our thought patterns or in our physical bodies and we need to pay attention to it. Your ex-flirting around was due to their own insecurity and seeking some kind of validation from others. Someone who is secure and content wouldn’t feel the need to do that, knowing it can cause someone else pain. Sounds like it wasn’t meant to be and that is okay. Find what makes you happy now and go for it. You got his.