Nothing is left now.?

Know that it isn't your fault. That's the first thing you have to realize. She was looking to place the blame on anyone because she was feeling guilty and desperate over her boyfriend reading those texts. Desperate people do desperate things. If she was really willing to throw away your lifelong relationship over something so trivial, there's really nothing you can do. You should give her space for her to realize the true results of her actions. She'll miss you like crazy. If she doesn't come back, well I guess there's nothing left for you to do. The ball's in her court now.