This would be perfectly okay IF their R is in a good place.
Don't ask (TELL) her to do anything. Be a big boy and call XXX yourself. Don't tell W that you did this. STFU is the rule. You are no longer a team.
As far as "I have something more important"...whatever it is...watching paint dry... SHE DOESN'T WANT TO WORK ON THE MARRIAGE.....you are agreeing with her. You hear her..you are supporting her decision. Again, this is not what you say to someone when the R is in a good place.
I have something more important = being an @$$hole about it. The point is you want to behave in a way that makes her think she's a fool for letting you leave. That comment would make me think I'm right to walk away.
There are other ways to make that line in the sand which would make her regret her choices, not celebrate them.
M 20+ T25+ S ~15.5 (BD) BD 4/6/15 D 12/23/16
"Someone I loved once gave me A box full of darkness. It took me years to understand, That this too, was a gift." ~ Mary Oliver
