Hey! Are you listening to me?

These kinds of things can be difficult matters. There can be a lot going on here.

From my own experiences, I know I find it difficult to keep up when my girlfriend jumps topics around quickly because my mind is focussed on prior discussions. Your boyfriend's mind could be similar in that it's too caught up on small details of random parts of the discussion rather than keeping up with everything that is being said. You must remember that men in general are bad multitaskers in comparison to women by nature. If the TV is on and he is watching and you are talking to him, it might not be getting through at all.

Also he might not be paying attention because he thinks your hot and he's checking you out while you talk. This has its ups and downs obviously.

He might also be one of those types who just kinda space out a lot and only things that really excite them get their attention.

You could try out some tests to see if he's just ignoring you or caught up with other things in mind. Phone conversations work well for this kind of thing because he can't stare at you then. Then what you could try to do is have some topics of discussion in mind beforehand and try to keep the discussion fairly linear and see if he can follow along.

How ya doing, buddy?