Don't tell her it was or was not a date. It's none of her business. She shouldn't even know how you met this friend anyways. You're always "out with friends". This is a great way to stop the cake-eating. Be brief yet polite, but break off the convos sooner. I would limit meal together and time together with your daughter too.
Your W is full of "it". This year is great: I went to the hospital for some crazy stuff, had an affair, broke my vows, lied to my husband, betrayed my family, had to get a new job, worried about my husband dating, and live like hell. Don't believe a word of it.
H 34 W 29 BD 3/12/18 Divorce Busted Spring 19
It is not things that bother us, but the stories we tell ourselves about things.