Why can’t the woman decide to go abroad?

M: What are you and your sister going to do for your holiday this year?
W: I’m thinking of taking her for a tour abroad, but she can’t very well leave her children. What are you doing?
M: We shall go to the sea. I wanted to go to the mountains, but I gave up when my wife insisted.
W: Leaving the rest of the family behind, I suppose!
M: Why do you think so?
W: You used to spend holiday, alone before.
M: Yes. They’ll be quite safe with their grandmother. Last year, I left them to a nurse, and my youngest son got ill.
W: You really shouldn’t have done that. When are you leaving?
M: Next Thursday. We have to send the children to their grandmother first, and maybe we’ll stay a day or two there.
W: I hope you have a good time.
M: Thank you. But why don’t you change your mind and join us? Making a large party will be great fun.
W: For my own part, I should love it. I’ll talk it over with my sister, and see what she thinks about it.