He still misses me and contacts me but has a new girlfriend, I still like him.. what should I do?

hooachoo
To put it simply I casually dated a guy that I met the last 2 weeks of college for about 2 months (LD after the 2 weeks). He was not over his ex girlfriend at the time (a one year previous one, not recent btw) so that's why we weren't official because he wasn't ready for a relationship. I know, red flag.. but he treated me wonderfully--talked to me for hours everyday, confided things to me , worried about me, complimented me constantly, and always wanted to spend every minute with me..He even invited me to go on vaca with him and his family. W e did have sex btw.. it wasn't just hanging out as buds.Basically, everything seemed perfect but still I needed to break things off with him for him to take me seriously and commit (he was dating other girls and it was hurting me). When I broke up with him he was shocked and told me about this new girl he was hanging out with saying she wanted to date him and he liked her but was confused and holding off because it "didn't feel right with what we had going." Now, the very next day after the break up he starts dating her (he's known her for 3 years btw) and 8 days later she becomes his official gf!

Now, he doesn't seem to be taking her seriously—I’m assuming the day they started dating they did something sexual and that day he was talking online with me while she was sitting RIGHT next to him on the couch.. why he didn’t say he was busy is beyond me. Though, on the other hand.. he said he was going to call me later that night and never did. Also, after only a WEEK of them dating.. he ims me on fb the very second I sign on saying eagerly "how are you?" almost as if he was waiting online to talk to me. Now, 2 weeks after that he liked one of my statuses on fb. Now, today he imed me again and talked for a really long time saying “school is starting again soon!” and I said “yeah, I’ll be back in 3 weeks!” and he said “ :) we will have to get lunch or something and catch up then soon!” Is he simply wanting to be friends and the girlfriend knows about this or is it something completely on him-- I wonder if things will change now that I'm no longer long distance. I am still so confused as to why he's official with her.. if he liked her that much why did he tell her he wanted to see how it would work out with me before dating her and now even after they're official is still initiating contact with me? He's not a jer, even though his actions are making him look like one.
He still misses me and contacts me but has a new girlfriend, I still like him.. what should I do?
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