pick up the check

"We let them set the terms, but we don't ask them to pick up the check. And I just find it frankly a little humiliating."

Tell her that your mother can’t afford to pick up the check every time they visit.

I say that because your mother’s desire to pick up the check may be more a matter of wanting to treat your sister and brother-in-law as guests, rather than wanting to demonstrate that she, too, can eat at fancy restaurants.

If you treat these families as single “units” and pick up the check every third time, the couple that pays is paying for five people outside of their family unit.

But every time you pick up the check, you are paying for eight people who aren’t in your family unit.