How Too Tell Him.......

How Do You Tell Your Boyfriend you've Lost Love For Him ? I've Been With My Bf 9 Months Been Knowing Him For 3 Years Loved Him At First Sight. I Fell Deeply Inlove With Him We Brokeen Upp Like 2 Or 3 Times . We Started Dating In May He Effed A Girl In Junee I Didn't Know Becausee I Was In Mexico I Found Out By My Bestfriend Back In August Or December! He Chosed Everything Before Me Like I Was His 2nd Choice . Now I'm Here Like Idk What To Do ? He Says He Changed And Everything and He Shows Me But Now I Don't Feel The Same For Him As I Did In The Beginning. 
I Didn't Leavee Him Becausee I Was "Inlove" I Guess You Can Saay That .