I think all you need to say to S12 is that Mom and Dad are working through some things. You don't need to go into any more detail than that, really. You might say that over time, sometimes people end up wanting different things out of life, and that may be where Mom and Dad are right now.

Whatever you do, don't lay all the blame on Mom...make sure S12 knows that it's 50/50.

This can be very traumatic for a kid, so handle it very carefully, Treeman. No blame.

Me: 54
Her: 50 and sexy as hell
M: 32yrs
T: 34yrs
Bomb: Sept 26-07 "lost our emotional connection"
Bomb 2: Dec 25-07 she's "not feeling desire"
She asked if she could come home Apr 26-08!
Everything's GREAT!