What is this kind of infatuation?

I mean almost 4 years ago, I had my 1st boyfriend, I was really heartbroken from what he did. I think it was just the attachment that made me kinda think that I couldn't live without him but I never really had feelings for that guy. Then after a year during my 1st year in college, I saw a guy and instantly was infatuated. Honestly he's not really handsome and his attitude isn't really my type but I'm really infatuated with him even after 3 years. When will this kind of infatuation end and what's the explanation of this kind of infatuation. He's just a friend and not even a moment he became my boyfriend. I honestly I tried everything to forget him but it is still unsuccessful.