Sorry he still being such a poop. I didn't realize he was still pushing you on those things.
For what it is worth, if your xH does pass away while the kids are under 18 you would get Social Security for them as their parent/guardian. My first H only worked half of the time and low paying jobs and I was pleasantly suprised how much I got for the kids. He was also only 34 when he died. When my oldest turned 18 back in 2004 I was getting around $700 a month for two of them. Then, because it was actually being split between 3 kids (one from his second wife) it then was split between two instead of three, so I was still getting around $500 plus when my second turned 18. No child though ever gets 100%, so his second wife did not get more when my son turned 18.
I had a girlfriend in a similar situation and her SS was double mine, as her xH earned much more than my xH. It does stop at 18 or high school graduation, and before 19 regardless of whether they have graduated, or not.
I am no expert, but it is my experience. Just something to ponder. I realize it is not the same as the lump sum that life insurance would provide, but it is what would happen.
Good luck...
Serenity