As to the first paragraph, your concerns are valid, your healing matters and you are not required to support your WW's schooling. You can offer to keep your D's at your house if that's an option, or you can say No if your concerned that it will set you back. I guess what I'm saying is you can do it if YOU want to, but you have zero obligation to do so.
As for the second paragraph, it's impossible to know if you don't have any more info. Maybe she wanted to see if you had someone over on Saturday night or if you were out... Maybe they went shopping near your house, or out to dinner, or were at a friends house, and your D wanted to see you. Just too many possible reasons to figure out, so try not to waste the energy.
M - 9 1/2 years 5/5/16 - Bomb drop - 3 week EA 10/31/16 - We sold house 01/10/18 - D Finalized