I can't cope when he's self-centered

I'm Pisces woman and he is a Cancer man. We began talking as friends and eventually developed feelings(I was cautious about it first, because of the long distance thing). He decided to take a step in having a more-than-friends thing, and sure I said. We were all in until he seemed to be lil off. We talked things through, he was going through tough times, so I was there for him. After a while, he started replying late to my messages, kinda a shift in his voice, and I decided that it was fair to put my time and energy over just being friends. He would continuously blame himself about how he didn't try harder to save it and I would reassure him that everything was alright, I'm still his friend. But then he began to be super cocky and closed. Therefore I was like listen: "I can last ages without talking to my close friends but when we really text to each other everything is just normal. Text me when you really want to talk. " We haven't talk ever since. My question here is how could someone be this close and robotic all of the sudden? What's happening in this cancer man's head?