Don't know what to do...

I was dating this girl for a year and everything was good the first couple of months while we were both in school but as the summer came we both had to go home. Mind you that she has never been with a girl before.  We really did jump into the relationship without thinking it through. But anyways she went home and told her family about me. Her dad flipped out, her sisters called her disgusting and her friends were horrible to her.  After that our relationship wasn't the same.  All these conflicts with people and our families caused a lot of fighting. Also the lack of time together because it was a long distance once we left for summer, caused as to argue more.  All we did was argue for the entirity of our relationship to the point were we couldn't even tolerate each other. We fought maybe once a day over petty stuff.  Another thing that added to our stress was the fact that we are both devoted Christians.  This caused extra problems such as, if what we were doing was wrong.  She finally gave up and said she couldn't do this relationship anymore because she felt like God didn't want us together and that she had no peace about the situation. The only way she had peace was being with a guy. I was heartbroken. I felt not good enough because I was a women.  Maybe a few days after we broke  I found out she is going on dates with this guy from her work who she swear up and down she didn't like.  Come to find out that she did like him.  I couldn't Believe her because we just broke up.  Me personally I couldn't think of another persons in that way because I still loved her. Her response to the whole situation was that " oh she is single and can do whatever she wants" . After I found that's out  I stopped talking to her for a month. It was the hardest thing I ever done.  But by the end of the month I felt peace about the whole situation. Now here comes my ex telling me she still loves and cares for me after a whole month of her being so mean to me.  She tells me she doesn't like the guy anymore and wants us to talk . So we talk and end up sleeping together.  I go hang out with her after that happens  and she calls me on my way back home saying she can't do this. She has no peace again.  I'm like okay. I can't argue with that.  Maybe God really doesn't want us together.   I was heartbroken yet again.  But I told her I would be her friend because we had a really good friendship. We ended sleeping together again and acting like we were a couple.  She told me again that doing those things gave her no peace so we stopped. Come to find out she is with that guy she said she didn't like anymore.  I asked her how can u stop liking someone and then start. Mind you they slept together the first time they dated. She's like idk.  She tells me she is over us and she wants to do what she is suppose to do, which she means by being with a guy and getting married.  I asked her how can you love and like someone at the same time. Don't you want to get over the other person first? She said she just moved on and she's sorry that I haven't moved on as well. Idk what to do anymore. I'm so heartbroken and I'm wondering why God would let me watch this play out before my eyes. It seems so cruel.