Friend disappears without explanation

It was two years ago. I studied with a guy in the same school, we communicated very well and closely, I positioned us as "friends", but everyone around said that we were dating. I always denied it, said that we were friends and nothing more. He kept silent, or simply ignored it, or pretended not to understand, in short, I don't know.

But everything was great, I was happy with everything, and he seemed to be happy with it too. We were in touch 24 hours a day, texting, calling, walking (in a group or just the two of us), I didn't have time to go tosocial networks he wrote right away. But one day, as if he was cut off, he stopped writing, calling, I thought something happened, and asked "what's the matter, did I offend you somehow?", to which he said "everything is fine, why do you think so?"

Then he wrote to me, of course, but less and less, for a month he still showed up and let me know about himself, and then he disappeared. But through acquaintances and girlfriends he was still interested in my life, what was going on with me test-antibiotic.com, he liked photos on social networks, but did not write. For me, of course, this was a very unpleasant moment, because I did not understand such behavior. The only thing he congratulated me onbirthday , but the congratulations were so cold that it would have been better not to congratulate. A year passed, and he actively started liking my photos, to which I responded by going to his page and liking a couple of photos, and then he wrote to me, we talked, he said that he misses me, that when we meet he will definitely tell why this happened. He asked about everything and that's it, then he wrote a couple of times and that's where it all ended.

Another year passed, and he showed up again and the same situation repeats itself, now everything is much easier and simpler. Then, a year ago, I still had resentment because of how he acted. Now everything is different, we can write to each other, laugh, I think it is because I cooled down to this situation and let it go, now I am absolutely calm. Although after we stopped communicating, I myself wondered if test-antibiotic.com we really weren't friends and we were in the "friendship-relationship" phase. That is why it was so difficult for me to accept what happened, now it is difficult to say.

I only have onequestion , I described the situation, I want to hear your opinion, what could have happened? Why did the person get knocked out?