Was He using Me?

it’s a long story but I really could use some insight.
there was this guy I met at school, and we started texting and talking a lot pretty soon after. I always noticed him talking with this one other girl in school but didn’t really think anything of it. it was soon made pretty clear that me and him were going to be together, yet he was still talking to her pretty often from what I could see. but I wasn’t concerned, because one day he told me that he told her that he was with me, and that’s when she started crying and told him to f_ck off.
if she had that kind of reaction, it makes me wonder what was going on between the two of them… right?

we had a good relationship… he talked to me and made time for me a lot, included me with his friends, always was thinking of fun things for us to do, paid when we went out, etc.
he told me that nothing had been going on with her, that he was with me. then I guess she texted him a few days later, but he wouldn’t tell me what she said. then the next day he dumped me… for her. turns out she was his ex girlfriend that he dated before for like a year or something. I’m having a hard time understanding where all this came from. does it seem like he was just using me the whole time?

He might have been.  Or he might have wanted to play the field.  Or he wanted to have two girls interested in him at the same time.  Or he was really more into you for a while than he was into her…..  All kinds of possibilities.  Sometimes we simply have to chalk things up to a learning experience, and realization that maybe we liked somebody more than he liked us.  Now that you know how he operates, isn’t it good that he moved on?  You should do the same.