G.♣.
I think the only thing you can do is to nicely say, "Dad, I appreciate your perspective, but we have made our decision and I would like you to respect that."
He's entitled to his opinion, but you do not owe it to him to do what he says or wants. Because this is the way he's always been, I do understand how you might second guess yourself. But you are a grown woman, and you and your husband make decisions for you and your kids, not your dad. And you don't owe him an explanation.
"Thank you for your input, Dad, but we have made our decision."