I shouldn't love you but I do

“Have you ever been in love with someone that you shouldn't be? I have tried to fight my feelings but it's getting harder and harder. I hated to admit it but I was in love with my sister's boyfriend. I know I am a horrible person but I was in love with him way before she got with him. Sometimes I think she knew about my feelings and that's why she went for him. I just didn't know what to do anymore...”