Even acknowledging that women take any opportunity to use men as heavily as they can get away with, it's interesting how it got to the point of surprise-offloading her kids onto a friend while on a trip so she can have the vacation to herself. It's quite the Hail Mary, so surely their friendship dynamic already had a history of tolerance for this kind of thing, which perhaps explains why the guy rolled with it the first day: he genuinely doesn't mind helping from time to time, even if he realizes there isn't an actual reason for him to do it.

The day that follows is very typical woman behavior: instead of being thankful for the effort someone else put in improving her life at no benefit to him, she ponders, can she get even more out of him? It's the same base thought process that fuels hypergamy, an unrestrained need to maximize her quality of life at the expense of others. All women suffer from this, but single mothers more so because they don't see their fatherless kids as a consequence of her own bad life choices, but rather a justification for the world owing her something. That's why a relationship or even a friendship with a single mom is a waste of time, they have no value beyond being used because they'll just use you whichever way they can.