Tostada, I don't have anything to add really beyond what KK has said. I doubt that there is anything that you can say in the card that will work a positive benefit, but, I think that there are a lot of things you could say that will work against you.
Just my opinion here, but, you getting on with your life without her is in my mind the only thing that has potential to bring her around and no card is going to show her that. I'd get a card from the kids and leave it at that if it were me.
Also, I don't know why it wouldn't be realistic for her to watch the kids while you go out. You don't have to specifically ask if she will watch the kids while you go on a date, just, can you watch the kids on Saturday night, I have plans with a friend. If she won't then get a sitter and go out anyway.
That's my opinion. I understand that you might not be in that place. I also understand that I was in a very different place only a month ago. So, I offer this up as just another option for you to consider.
