Guys, Honestly confused. Why did he end it, if he said things between us was going really good?

We are both 24 years old and have known each other since high school. And we started te ting each other. And soon it was official. But then he, just disappeared. Out of nowhere he broke up with me. Claimed long distance was too hard. I knew long distance would be hard, but he convinced me we could do it... so we becamea long distance couple. A month later he breaks up with me because of it. Claimed he wasn't mature enough for a relationship yet too.

I kept asking him if we were good. He said everything were going really well and he was still happy.
Guys, Honestly confused. Why did he end it, if he said things between us was going really good?
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