I agree that you should not pursue right now. But we women find things sexy about guys that that don't even realize. Maybe it's the way you prop up against the wall......who knows. But she'll see that in you, especially when you are looking & smelling good.
I think the "game" she was playing with you while shopping went a bit far, but as you said, she blindsided you. She does seem to respond when the two of you are keeping things light and even kidding around. That is why I think it's important to try to keep a fun atmosphere as much as possible. Your kids are just the right age to get them down on the floor rolling around and tickling them. Nothing can make a woman smile than to hear the giggles coming from her children. Who knows.....you might even get mom in on it too!
You might expect to be blindsided by her if you cause her to think you are getting your hopes up about the M. You could consider some things to say in response and have it in store to use. She will bring up about getting remarried again.
I could always tell when my H thought everything was honky-dory and the problem was fixed.....and maybe all I did was smile at him. So, I had to act mad or disinterested just to let him know nothing had changed and not get hopefull yet. I know that sounds awful, but a lot of W's are the same way, they just won't tell you.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!