Do I stay or do I leave?

If an ex goes out of their way to reveal something very personal and sensitive about you to other people then you simply shouldn't trust them because who knows what kind of stuff they may have told other people behind your back? If he really loved you then he wouldn't have done such a terrible thing because that's him going out of his way to deliberately hurt you. You really are best off moving on for good and find someone else or like you said, just go solo for a little while, enjoy yourself and fix the things you feel need working on. Don't worry, you'll meet someone who will really care about you eventually.