Im in a love square..?

I just don't know what to do. i have been in a relationship with a girl for almost five years and i love her to death but i don't feel it anymore there's no pion from her. just recently we caught up with a girl we went to high school with and we all had a immediate connection. both girls are ually attracted to each other. the next day i find out she is also attracted to me. this si where it gets complicated she is also in a seemingly failing relationship. I am extremely infatuated with this girl because she gives me the things i need from a girl, recognition that i am good looking and me qualities are appreciated by another human being. me and the two girls did get close to a ual experience and it seemed like everyone was in favor of it. the girls want to be together and the other girl wants to be with me,but my girl wants me to have no part which makes me want to be with the other girl even more because she is the only person in this relationship who cares how i feel. I am just so confused should i just back off and force my feelings away or should i tell my girl how i really feel. Please help.......