Super confused

So if you remember Carlos moved for college. Well he still texts me all the time and whenever I get on facebook he has to IM me right when I get on. Weird right? well idk what his deal is I thought when he moved away he wouldn't talk to me anymore but I guess I was wrong. He still flirts with me but here's a juicy detail that I recently found out. He had/ has (not totally sure) a girlfriend when he was texting me one of my girls told me that a few weeks ago. Which I have no idea why he would be texting me when he was dating another girl but I'm kinda thinking there might be more to our what I thought was innocent flirting. Most guys wouldn't keep it up for this long would they? Its been 3 years and whenever he breaks up with a girl he comes back to me. I just don't get it! I wish guys just told us girls what was on their mind sometimes I mean the stuff besides sex. Its not like I would mind if Carlos had feelings for me even though hes so far away he will be back for breaks and summer but who knows what that boy is thinking. I guess ill just go with it and see what happens until then I shall stay super confused.