There’s little point having the talk while he’s using, in fact its dangerous. So Just take some time out for yourself.
Him asking how you are and what you’re up to, is just his guilt, it makes the user incredibly selfish. (what other drug would reduce all inhibitions and morals to let users think it was fine to cheat).
He knows what he’s doing is wrong to you, but wants to keep you dangling on the end of the phone for when he wants you.
You should be his priority, I know this now x