He is definitely bringing up you dating to make himself feel less guilty. That is a projection. You handled it fine, even though he may not have liked it.
You are wanting to go to your kids' college to tell them what's going on? Seems like the separation rules are simple:
1. Person who wants to separate needs to GTFO. 2. Bills 50/50 3. No cake-eating
Don't worry that you've fallen off the wagon, everyone has. Just recommit and get back on! I only have the halfarse, in home but not really, no rules discussed "separation" b/c my spouse was having an affair experience. I wish I could give you more advice on this.
H 34 W 29 BD 3/12/18 Divorce Busted Spring 19
It is not things that bother us, but the stories we tell ourselves about things.