Confused...

I can't seem to stop thinking about him, and him is not my husband.... He is just some guy i fooled around with 3 years ago, someone i knew just wanted one thing, someone i knew would never take me serious, someone i was head over heels for long before he noticed me. Someone who cut me out of his life as soon as i told him i didn't like something  he was doing while we were fooling around. Someone who i can't stop thinking about or dreaming about. Someone who isn't even in my life, he is just on my instagram feed. Why can't i stop thinking of what my life could've been if i had given him what he wanted? Would he have taken me serious then? would he have actually dated me instead of just having me as a booty call? I wish i had the answers to all my questions but i know i won't get them and even if i do get them it wouldn't change anything. I love my husband and i would never leave my husband for some ass hat who just wants to get laid. i just find it frustrating that i can't stop thinking about him, hopefully its just a phase thing.