I cant get over my ex from 17 years ago?

i was with a guy for only a few weeks when i was 18 and that was 17 years ago. i fell madly in love with him. he 2 timed me and i broke it off. since that ive been in long term relationships and even engaged but i never got over my ex. my heart aches when i think of him. hes now married and hes been in contact with me via facebook and wants to meet. he told me he 2 timed me as he was 2 young for a relationship back years ago. i think were made for eachother. he doesnt act like he has feelings for me as he talks very sexual but after 17 years since we 1st met its bound to mean something that he has contacted me. why didnt i get over him? i cud sit and stare at him all day and id marry him in the morning. i dont know what to do.