Just when i thought i forgot him.. he reappeared and i just remembered why i loved him more than the others?

About a year ago we stopped contact for good.. Back then He knew i adored him but he lost interest in me obviosly and had a girlfriend and refused to have a closure with me back then,, so i was insulted and hurt deeply.. Now a year from that day u met other guys, well as i thought started to have feelings for another guy who is very close friend but ts complicated coz he already got a gf.. Anyways, im trying to convince myself that i can love others than the first one... But when i saw him in a party after one year of the day i fought with him.. I had those feelings again,, "why i loved him not someone else",,, the way he smiles, the way he talks, move, looks, the way he thinks and express himself,, how shy he can b sometimes but cover it up with a cold look.. I adore him.. I couldnt stop myself from starting a convo with him.. Then the rest of the party he acted liķe i was invisible :( he knowed a few people in the party and he was just sitting alone for most of the time,, even the guy whose the party is party is for was astonished he came since they were some old friends then hated each other.. anyways,, i want someone just like him,, i know hes a good hearted person although he is hurtful sometimes... The thing is ,, i dunno wht to do,, how to act ,, how to treat him when i c him from now on,,.. I want to forget him but i love him,, :(