Replying to Women... Can't live with em', can't cut their throat and watch em bleed slowly...

So I got fucked over yesterday worse than I ever have before. Me and my girl have been going out for 2.5 years. We're in love, stuff is going great, yada yada. I'm on a workterm away from home right now. Some people call me crazy, but I never mind when she goes out and stuff. She came from a relationship where she was cheated on and hurt really badly. So I guess I knew that she would never do that to me. We'll she never cheated on me... but she did tell me that she fell for another guy. She isnt sure what she wants to do but she has to think about it. she is either going to throw us out the window and go for this dude she has known for 1 week, or continue with me and rebuild. Now I'm in complete shock over this. this is not like my girl. We were pretty much ready to settle down, so this is some crazy shit I have to deal with. question is, If I really love her do I give her a chance if she decides to go with me? or do i not wait for her decision and break up with her knowing that things will never be exactly the same again. or do I go on a murderous rage and kill them both and cap myself afterwards? fucking women.