Hi, I have been in very similar situation as you are. I am 20 and he was 26. His name was Alex as well. We met online and continued talking for nearly 6 months. Everything was going well (or so I thought), but one day he started to act differently and it stayed that way. It was like you described, he used to message me but it seemed like he didn’t want to talk at all and talking was just weird. It was making me very confused.
So, from my experience the best you can do is to move on and try to forget him. If you keep coming back to him, you will probably end up hurt. I know it may seem cruel, but if he wanted something more than entertainment he wouldn’t act that way. For me, this kind of treatment shows lack of respect which is the fundament for every sort of relationship, even just for friendship.
Though I run this site, it is not mine. It's ours. It's not about me. It's about us. Your stories and your wisdom are just as meaningful as mine. 