So I guess I need everyone to talk me out of being here tomorrow when he shows up.
It isn't a big deal whether you are home or not when he comes over. The key is how you handle the situation if you do stay. As long as you don't pursue him or get emotional in front of him and stay calm, cool and collected, then it could even be used to your advantage.
He has no power over you. It is only in your mind if you think he does. You have been doing just fine. I would assume he puts his pants on one leg at a time like most all men do.
So to conclude. Don't make being there or not being there a big deal that is causing you to worry. If you want to be home, then be home. If not, leave. He has been coming toward you and not the other way around. This would lead me to think that he is going to be the one that is going to be on pins and needles. He just wrote to you to tell you that he is sorry and wants to try again. Even if he didn't walk on razor blades and come crawling to you, it still shows and tells us that he wants you back. Just remember that he is still with the OW and there is no reason for you to share with him or any other man like that.
Trust in yourself here. You are fine. Believe that.