You say you need to detach more, and that may be true but your GAL activities seem to be gong pretty strong. Maybe you need to just shift your attitude a little.
Do you see it as a positive that your W chooses to have dinner with you and the kids? Seems to me like it would be.
Regarding the nephew, it sounds like he is a needy child and it is good that you/W are there to care for him. My only caution is if you decide to adopt and then the M continues to deteriorate, then you've got another headache on your hands. Not to mention the emotional upheaval that would potentially cause to your nephew. Just be careful, is all I'm saying.
Oh, one other thing regarding your post from the other day. You said that after things began to deteriorate with the kids when your W was leaving, you said "Welcome home". Was there just a little snark in that comment? If not, do you see how it might have been interpreted? And, how does that get you closer to your objective. Just something to think about, SIAS.
Keep plowing ahead.
Me51 W53 S17 S14 M22 T25 Bomb-9/11; A-11/11; I move out 11/11
It's easy to find our bottom, it is our top that requires cultivation.
Every rough spot adds to our emotional constitution. -Barney Fife