My sister and I are planning a vacation to Mexico with our families just before christmas. My dad got wind of our trip and is asking about where we are staying etc. We would love for our dad to come, but his wife drives us crazy. It's all about her - she is so selfish. In fact, I don't really think my dad wants to come (he has had melanoma) and is not good in the heat - but she want to go and is pressing him. If my husband finds out she is possibly coming, he is going to have a cow. How do I nicely tell my dad that we would love for him to come but not his wife?