I love how you put that you wanted to "shrink your world back down to just you and the kids" to help you feel better. Do this. Fill the calendar, be alive and fun with your kids. They will feed off this and feel better too. When X has them, fill your social calendar BUT NOT WITH DATES!!!
Also, when I say 'shrink' your world down, I don't mean keep X from the kids at all. If your son is asking for more time with Dad, I think that should be worked out for sure. Not saying the 1 week on, 1 week off things, but maybe some alone time for him and Dad.
Donna, you are back. You stumbled and picked yourself up. Now, go enjoy the rest of September!