How to get over the guy i like?

he has a girlfriend, he's had one for like 4 months now. but he's just amazing, everytime i talk to him hes soo nice. he knows how to treat a girl, im so jealous of his girlfriend /; . i wanna get over him, but when i starrt to, he'll talk to me and say something cute that makes me want him again! he knows how to make me smile, and laugh, and surprise me from the back and grab my waste. But I dont wanna go forever liking this kid cus i dont think theyll ever brake up, anytime soon anyway, and im gonna getting hurt, and its not even gonna be his fault ; how shouldd i get over him ??!! /;