Leave out the sentence of how you asked not to discuss via email. He knows what you asked for. You reminding him will be seen as nagging.

Leave the first part letting him know about open house, etc and say something like

Since we have not discussed scheduling for the kids during the school year I am making a proposal. Please let me know if below works for you.

Or something similar.

yes, you de deserve to be treated better, but don't expect that right now. You will only be disappointed.

Sorry you are going through this. It sucks.

BFM

There is only one person who could ever make you happy, and that person is you.
David Burns, Intimate Connections