I would tell the kids first that you will be telling W. Then immediate go tell W. But that's just me. I wouldn't want to tell W and then have her storm into the kids room freaking out that daddy is leaving.

As for telling W you could say she may be getting solicitation mail from various lawyers in the next little while and this is why...

FWIW.

Breathe. Take some time out for yourself and chill. Read some Tao Te Ching.

M: 59 W: 53
M: 9 yrs
T: 14 yrs
No kids together but D30(hers), S27, S24, D21(all 3 mine)
W moved out 11/18/2013
D-Day 12/14/2013
W moved back home 12/1/2014