Ah...that's a more difficult problem than your original post made it seem. I can see how you'd be upset by the response, since you know the details of the situation.
For what it's worth, I don't think he was questioning your commitment to your children, so much as the forethought you put into the process. He just didn't do it in a diplomatic way.
Being someone who probably overthinks some things in my life, I tend to equate "not thinking about" with "not placing much importance on something". However, being something of a complex system, between family, work, society, and other factors, it's just impossible to calculate, even though we have clear, if rough ideas about what we'd like, and how we think things ought to be.
For what it's worth, I don't think he was questioning your commitment to your children, so much as the forethought you put into the process. He just didn't do it in a diplomatic way.