Most Helpful Guy
Same thing happened to me. My ex and I met up after not talking for a year. Started dating when ever I came back home from school. Then I was back for the summer and we spent every day together. Kinda opted to do a long distance relationship. She cried when I left. We talked on the phone every night for the first couple weeks then the same thing happened. Kinda disappears for a night or a day. I came home she was a little distant but not too bad we still had sex and what not.
Left and then came back the next time 3 weeks later and she was super awkward and said she didn't have feelings for me anymore. And I found out she had started sleeping with some other guy.
It's pretty common in long distance relationships, It really takes two devoted people who actually love each other. Not a fling type thing. It's very hard work and it sucks not seeing them, so if one person isn't fully on board then it's going to fail.