LOL. Very unlike you, I nearly always use public restrooms every time I'm out. My shopping tolerance is 2-3 hours, my bladder capacity, about one hour. Plus I have IBS. Rarely do I get through a grocery store or Costco without hitting a restroom at least once.
Like me, when your kids were little you'd use them as an excuse to use a restroom in a store that didn't generally permit public use. (I'd cast my eyes down sorrowfully at my child and say with a cringe, "Do you have a restroom I can take him/her to?" They almost always allowed it.)