I agree with CB. If he really has accepted that it’s not going anywhere for the two of you, he won’t find it strange if you communicate with him less. You said you want to concentrate on your studies so do that and he shouldn’t kick up a fuss if that’s your excuse if he asks you why you’re not around. Don’t be online so much etc.
Hopefully things will die out on their own (unless he’s a nutter and can’t let go).