Usually when I'm non-responsive like this, it's because I'm feeling overwhelmed, be it due to outside circumstances or because the person I'm talking to is kinda smothering me. In my subjective experience, a lot of women -- not all -- take it personally and get offended when I express my feelings and needs to them, which then makes me not want to communicate them at all. I know that's a flaw on my end and I'm working on it, but it's something worth reflecting on.
Of course, it's also possible that he's just plain old old inattentive and bad at communicating. Or he doesn't like texting. Doesn't hurt to ask.
