When I have a discussion I'm not happy with, I replay it with how I'd like it to go next time. Example:
W: Hey, I just want you to know I'm planning a five day trip to Florida in March and want you to watch the kids.
Chris: That sounds fun. What are the details? I'll make sure to take the time off of work.
In a normal relationship, sure.
But she FIRED you. Why would you volunteer to take off work so she can go party in Florida? Shes an adult - she should be the one figuring out those kinds of childcare arrangements.