The store ran out of mini tacos?
My
theory is this:
Since the big guy promised everybody his demise was imminent, so as to get ready for her life after Steve, poor dear Marta started window-shopping around, for a potential second husband, preferably one who'd take care of her, instead of her taking care of him, as has been the case in the Dawes household the past forty years.
She probably looked too longingly at some guy, and the big guy's now having a cow about it.