"Supposed friend", Steals my girlfriend.. NEED ADVICE!

Hello,

I need random peoples advice please!
What would you think of her??
What would you do??
What would you have done??

Alright,

First of all I would like to say she threw away an 18 month relationship with me to be with my "supposed friend" that lives in a different state... A DIFFERENT STATE!! Left me for a long distance relationship... The guy had to move away because everyone hated him here and he couldn't get his life together. So he's trying somewhere else. What makes her think hes going to be able to handle a long distance relationship let alone his own life...

Last week, I took my girl to Disneyland for Valentines Day. We were dating for 18 months. Everything was going great. We had an amazing time. We came back this past Sunday and she started acting funny. She had started talking to my friend alot. He started seeing her on a daily basis. They would always talk. He would always text her and call her to see what was going on, but never called me or texted me... EVER! They started talking more and more, then she broke up with me on Friday. Then the next day, (Saturday) she went out with him that night and they ended up having sex. The whole nine yards. She tells me the reason she broke up with me was because I wasnt treating her right... Is that a good enough excuse to go and **** my " so called friend" the day after our breakup? She told me that we were broke up, so it didnt matter if they had sex or not. SHE HAD SEX WITH MY FRIEND ONE DAY AFTER BREAKUP!! She doesnt want me to tell anyone that they had sex. Why do you think she doesnt want anyone to know the full story?? She leaves out the sex part when she tells people about what happened. Why is that? What would you think of her if this was your girlfriend, friend or stranger? How would you have reacted, how would you still react? What advice then can you give me?

If you could take just 2 minutes out to help me, I would greatly appreciate it. THANK YOU!

I'm so sorry. =/

Well, I'm sure anybody would leave out having sex with somebody else the day after breakup. It could come off as that there may have been something already brewing or that she's a sl__ by sleeping with another guy right after. (Not implying anything.)

Did you ever talk to her about what was going on with the other guy before the breakup or did you just watch it pass by?

It may sound cliche, but it's better you find out earlier than later. It could've been worse, you could've spent 5 years with this woman get married and then something like this would happen anyway. Imagine how much worse it could have been. Now that you have this psycho out of your life and now that you know who your friends are you can move on and find someone right for you.