My girlfriend wants out of the relationship?

Hi.  I've been in a 5 year relationship and my girlfriend has cheated on me several times but I've forgiven her and moved on with our relationship.  Everything was going good for about 6 months and I now all of a sudden with no warning she has moved in with some guy saying that's where she wants to be now.  I'm heart broken and know I should let go but something is still in me that wants her back.  How do I let go of someone I love so much?

Dude, your girl left you for another man and you still want her back.  Grow some balls and just move on.  She's no good for you Bro!

Losing someone you love is one the hardest things to bear, but if you don't respect yourself no one else will either.