Can't get him out of my head and I'm married!!

Well a little back story- I got my first bf when I was 15. We dated for 3 years until our senior year. We were each others first EVERYTHING and like any other 15-18 year old girl I was madly in love. The breakup was one sided- he wanted to experience life apart and we were both planning on going to different colleges-- ff to 3 years after high school when we were 21- I was back in our home town and this man was living in another state. We reconnected somehow and I was sooo happy! He moved back to our state. We didn't last too long- about 8 months before things ended once again because we were still so young.

To present day--- I am in my early 30s and been with my husband for almost 10 years. We have a child together... I am mostly happy with my husband- we have our problems but nothing big. Anyway I cannot get this old boyfriend out of my head!!!! He is married and expecting baby #4! I have dreams about us being together and in my crazy mind I love him! What is wrong with me???? Our ship has sailed. He is very loyal as am I to our SOs so i would never try to reach out. I know this will never go anywhere but I think about this guy like daily!!! Heeeelp!!