D, I keep thinking about this, and am having trouble with how to advise you.
You're still determined to wait until after the holidays to have a talk, right?
Your biggest concern is you don't want to get stuck in friend zone?
You want to pull away, so she has to pursue?
I think I see it. Get busy. Get so busy you don't have time for her. You get sucked in when you're doing things with your kids together. Start talking on the phone. Text someone. You are so busy with your new life. When she sits next to you, get up and move away for privacy. Is she asks who...ask her why she wants to know.
You're enjoyment of the friendly interactions is what is making it hard. You've gone past pleasant into buddy-buddy. Pull back. Now. You don't have to explain...You're just so busy.
She left you. She wants to be friends. You said, "no thanks", and yet...there you are.
