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First of all seems you knew that she wasn't looking to be a Mommy. Now that she's said well "maybe 30%" you want to push the issue. That means she's 70% sure she does NOT want them. Do you really want to possibly ruin what sounds like a great marriage?
Have you talked about if you did have children, who would the various duties? Who would stay home from their job when the child is sick? Who gets to work late and who gets passed up on the career track because they have to be home when school is out and take time off for sick children and doctors. This is a career move that usually can not be made up. Will she resent you if this happens to her?
I say keep your life as is, but maybe also join Big Brother/Big Sister to meet those needs you have to nurture children. Or volunteer and the community center or to coach soccer. Baby sit for your friends. There are many ways to have children in your life part time.