He's so hard to read?

*PLEASE READ CAREFULLY AND BE DETAILED IN YOUR ANSWER*
There's this guy I've known for about a month. It's kind of a long story and I've asked about him on here a few times but all the details are important I think. I'll try to make it short. He's my roommates best friend, we started as friends. We became really good friends pretty quick and I developed feelings for him early on. He would message me all the time and I thought he liked me too. Once he found out I had a thing for him he told me he didn't like me like that and that we were just friends. That was fine it's not like I tried to initiate anything or pressure him. A few days after that he comes over even though my roommate wasn't home and we hang out all day watching movies. At this point I figured he had no romantic feelings for me, after all that's what he said. I thought we were just hanging out. But he became really touchy and affectionate. He kept his arm around me and found any excuse to touch me. Later that night he gets kinda drunk and stays the night. We had sex. He was sober when we did it and he's the one who came onto me. After that he kinda changed. He still messages me pretty often but his tone is different. The only time he shows affection now is when he's had a couple. So obviously part of him really does like me so why won't he show it? Also he's gonna be in another state till September and he said he would message me when he got there but he hasn't. It's weird cause when we talk he seems completely normal, but different? I'm so confused! Why is he doing this? Maybe does he not want to start a relationship while he's gone?
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He's so hard to read?
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