cassie,

I can only imagine the way you felt when you heard this. It must have felt like a kick in the gut. Kids usually do what they are told in those situations so IMO it's your x who's telling them to call her that. Bottom line...as long as she treats them well that's all that matters. They know who their mom is and they are only there 6 weeks. Encourage a relationship with them and their new stepmom, pretend itdoesn't bother you when speaking with them or with x/stepmom. You sound like you have your mind wrapped around it already, good for you. Hang in there.