Honestly? He's "punishing" you for daring to tell him that you want him to get off of the fence and get rid of the OW. He's ignoring you, so that you will chase him, thus proving to him and to you, how important he is, how desirable, and how much you cannot do without him.
He is taking your power and your dignity from you.
You cannot force him to do anything. You do not have the power. The only person you can force is yourself. So use that power.
Stop trying to communicate with him. Get to a lawyer. File. Move his possessions out of your room and into another room, or hefty bag them on the lawn. Serve him with the divorce papers the minute he steps off of the plane or out of the car.
As long as you allow yourself to be Plan B, he will continue on happily making you his second choice. Step out of that nasty little loop and start a new path. IF he gets his head out of his ass and comes to his senses, you can always put the divorce on hold, wait, or cancel it. But now is the time for you to act with pride, strength, and courage. Weak people are not attractive. Strong people are.
Find your strength and draw your line in the sand. Or have sand kicked in your face for a long, long time. (((hugs)))