Did you tell him that you wanted him to come to bed?
"Why don't you play (game) while I finish getting ready for bed? It should take me about 45 minutes. Sound good?"

Also maybe talk to him at somepoint while he is not gaming and ask if you too can come up with a reasonable amount of time for him to game in a day/week. That you two should have your UA time before he games. Or he gets a certain time slot each night to game so you both can plan around it.