I’m married and thinking about my ex lately

I don’t know why but lately I’ve been thinking about my ex more than before. We ended things years ago but he was the first guy I really fell for. Our sexual chemistry was amazing. Anyway I’m married now but still find myself thinking about him and wanting to get in touch with him. I haven’t acted on it yet. And we are in different cities hundreds of miles away so we wouldnt see each other. But why do I have this sudden urge all of a sudden?

We’ve been married 3 years and maybe I’m just looking for excitement? Am I bored? Is this normal or am I a self destructive horrible person?