I dunno Bob. How about you pay the bill and don't expect a single damn thing about it from your WAW. Don't even tell her or hint about it.

Zero expectations. Just something to tidy off the list and put your mind at ease.

Can you do that? Or by paying it or reminding her... you are expecting something secretly back? If that is the case. Don't pay it. Send her a message like this.

"This is your bill. I am not paying it".

And never speak or respond to it again.