first off, i'm sorry you're having to go through all this.
it sounds to me like she wants to break up with you but can't bring herself to up and do it proper like. my ex-wife was the same way. she still loves you and doesn't want to hurt you, but wants to move on.
it sucks when a couple gets out of synch like that.
she did have the courage and honesty to tell you about the other guy, which to me says good things about her character. that's infinitely better than finding out she's been lying and cheating.
the good news is you're still young and have three more years (at least
) of college to meet new people and have fun. same basic thing happened to me - high school gf and i went to the same college and broke up midway thru the second year. i ended up meeting the "girl of my dreams" after her and marrying her. those dreams may have became nightmares eventually, but that's another story
hang in there dude, time heals.