I am so very sorry you are hurting.

Please seek help and I know you'll get better.

When I asked my t why so and so did this or that (insisted on dating me while apparently having a gf), she said it's because he is unhealthy, lots of people are just too unhealthy to conduct their relationship decently. So it's not because of you, he is just incapable of normal relationship.

And sometimes when we are desperate we do this wishful thinking. So instead of paying attention to actions we just go by their words which we want to believe. Unfortunately nothing in your interactions with this guy ever indicated that you were in a relationship, yet you wanted to believe it was not a casual hookup.

Heck I was a victim of romance scam (I lost tons of money)yet I am middle aged professional with graduate degree and tons of life experience. Other victims are just as intelligent. It's nothing to do with how smart we are. Desperation does terrible things to our minds.

When you feel better get engaged in various activities that don't involve dating (for now), be out and about as much as you can. Join women meetups, go do stuff

But first get help from pdoc. We are all here for you. Hugs to you