Also, don't tell W where you go or what you are doing. Mystery can be VERY good, especially in a sitch like yours where the S shows even a teeny tiny bit of regret....
Don't hesitate to throw out a little something suspicious like... "Gosh, I can't believe how aggressive younger women are...." Hee hee!!!! Or "Wow, there sure are a lot of attractive, single women at my gym..." Then when she questions you change the subject and refuse to talk further about what *might* be going on in your life.
One more thing, when you tell W you can't take the kids, say it's because you have some important plans.... Of course, offer NO details beyond that.
And keep looking hot!!! Yeeeeah!
There is no arriving, ever. It is all a continual becoming.