Sometimes, I don't understand

So, yesterday, I found out the woman I was dating was seeing someone else. Unfortunately, I had to find out by snooping through her new phone. She had passed out drunk and I took the opportunity to check my gut feeling on the matter. And, my gut was right.

Now, I know it was wrong to look through her phone, but she would've never found out had I not found anything incriminating. Of course, it was the first thing she said when I confronted her about it -- "I can't believe you snooped through my phone!"

Yeah? Well, I can't believe you're fucking some coke-head Mexican from your job!

I think the most shocking aspect was the pic on her phone of her with this huge hickey. I mean, it's something more than I would have ever given her, even on purpose. It seemed she was real proud of it, too.

What I don't understand about this situation is.. why the fuck would one keep one guy strung along while nurturing a new relationship? I mean, regardless of the fact that she wasn't interested in exclusivity, shouldn't she be so inclined to let me know this? And, shouldn't she be so inclined as to let me know that she is dating someone else? I mean, she said she should've told me but didn't. She even lied to me about things until I confronted her.

I'm terribly angry, yet I'm so relieved that our "relationship" is finally over. I think, as time progresses, I will go through the stages of grief. How can I not? I just hope they go by quickly.

I'd like to think that my debt to bad karma has now been paid. I hope that things will go better for me in the future. Not that I believe in karma or anything.