<human>: Summarize the given text in a few sentences.

I moved away for work (she still had 1.5-2 years left in college) we decided to try long distance, we had been dating for about 6-7 months. I planned on moving back to the area after about a half year - year. About 5-6 weeks ago she broke up with me. She would call me constantly after we broke up (saying she was going to visit me, send me care packages etc) for about 2 weeks and then nothing. 

Anyways, I called her today because I might be moving back to the area earlier than expected and was interested in building back up our relationship. We had a nice talk and then she asked if I was dating I told her no (and told her about a bad dating story) then she told me she had been dating someone and trying long distance with them (she interned over summer about 6 hours from our college and he worked at that company). I asked her how long after she broke up with me and she said 2 weeks. She told me they haven't had sex and that they met after we broke up. She also told me how great he is and how she was instantly obsessed with him and how he's an engineer and how he's so outgoing and how she enjoys being around him. 

I feel like absolute shit. I should mention we lost our virginities to each other, and I still love her (marriage was even spoken about). About a week before we split up I bought her 2 sets of tickets to visit me (about 600$) and she was texting me telling me how much she missed me, loved me, etc. I thought it had more to do with the distance, but she easily dismisses as if our relationship was nothing now. 

How do I even deal with this? I know to cut her off although it looks like I need her to call in to get credit for those tickets. She doesn't see a problem with dating someone 2 weeks after our relationship. Nor does she think its bad to brag about her new date to me. Why is she being so cruel? I fear I'm going to develop serious trust issues with future relationships.
<bot>: Dated ex for half year, moved away for work, we tried long distance, she broke up with me, she started dating someone 2 weeks later and is now trying long distance with him.