The only thing that saddens me is that at what point does she decide 'enough is enough?' When does she start thinking of the kids and not herself? And I'm not talking about the kids not being provided for or loved.

But she will not live forever. When she passes away, how old will the youngest child be? 1 year? 2? 5 or 10?

Sure, to lose a parent for any of the children would be awful, but to lose a parent you hardly get to know. To me, that's selfish on the parents part.