That's pessimistic thinking - permanent and global. I think you know what to say to the kids but Mrs SP could use some guidance. It would be a real gift at this stage too.
I would talk to Mrs SP about the signal it sends the kids and her thinking. Their "lives" aren't "ruined." Help her see this doesn't cover their whole life time wise and doesn't effect every aspect of their life. The kids need to both see you love them. It's confusing to a kid to see their parent make a choice and then acknowledge that it impacts them negatively. (Confusing to me too.)
Just point out her behavior that is troublesome.
Cheers on Veterans Day.
Coach
M22,H45,W45 S21/18D12 Retain faith that you will prevail in the end, regardless of the difficulties and at the same time confront the most brutal facts of your current reality, whatever they might be.