PS, I know this is really difficult, seeing our kids in pain also causes us pain. But separation anxiety is common at that age no matter the circumstances of the parents. I can remember dropping my 3yo S off at preschool and I would sit and read a book for awhile to ease the transition but he'd cry, I'd try not to cry, I'd get in my car and cry. Get to work, call and see how he was "Oh the minute you left he started playing, he's good." Talk to other preschool parents, I'm sure many have similar stories.
So while your M sitch might intensify some of those feelings in your D, you would still be needed to help her make transitions.
So how can you help her navigate through this? And remember, just like we feel our children's feelings, they also feel ours. How can you help you D with these transitions? Can you have a routine built around dropping her off? What words will you use to prepare her for drop-off? How will you control the intensity of your feelings so she's not so affected by them?
This is hard stuff, but worth it.
Me 57/H 58 M36 S 2.5yrs R 12/13
Let me give up the need to know why things happen as they do. I will never know and constant wondering is constant suffering. Caroline Myss