If you need 24/7 attention, do him a favor and move on.

I've been upfront with guys I've dated about needing space but they still don't get it and take things personally. I even ASK for space and its held against me. Sometimes I am so emotionally overwhelmed that I need to be by myself. Sometimes I simply CANNOT talk. (Odd concept that is misunderstood by most, but yes, the speech/communication part of my brain shuts down.)

Again, if you expect this to be like a "normal" relationship then move on. Oh, and if you're just 'talking' to him, he doesn't owe you much of anything. I am surprised that people say he owes you an explanation when you're not even a couple. If I don't talk to my friends for a few days, I don't owe them an explanation. Things happen, life happens. Give him space.