5 years ago in college i had a hookup fling with this guy. was never anything more than a hookup, but the night we met was a really great night. some time into it, i started seeing someone, and when he messaged me to see each other, i told him i had started to see someone and wished him good luck. we havent spoken since. its been 5 years. i was in a nearly 2 year relationship and would have phases of being unable to stop thinking about him. i am now in another 1 1/2 year long relationship, and am once again in a phase unable to stop thinking about him. he did reach out to me a couple months ago and i left him on read, and he unadded me. i'd never cross a boundary in my relationships. i love my boyfriend. its just so annoying, bc like i said, ITS BEEN 5 YEARS. and we were never ANYTHING. i dont understand why i get in these phases of just being stuck thinking about him. and i know its terrible, and again i dont act on it or do anything. it is just so frustrating. idk what to even do.