why?

why people need to love? why god created use to love someone? why we need to have a heart to love someone? can we just forget the person that we love? can we? how to forget? someone please teach me how to forget someone that i shouldnt love... i already hurt so many people. i dont want hurt more person already especially the person i love have such a nice and good person taking care of her already. why? why? why i want to love someone that already had a partner? and making that person sad everyday. i am sorry... please accept my appologize