Self sabotage?

To be quite frank, I p*** myself off when it comes to dating. I over think, I'm insecure, I don't believe a word anyone says. I've had horrendous abusive experiences in relationships and whilst dating. I'm aware of red flags, I've been to therapy, I'm happy in myself that I won't make the same mistakes again. So why do I meet a lovely guy who isn't actually doing anything wrong or red flagging and I still start convincing myself that he's the same and I don't want to be doing this. Ugh I annoy myself.