I know the obvious thing here would be to just ask him 
BUT if he gets a sense of me pushing the idea then he will just push back and say no. He is someone who needs to come to this way of thinking in his own time.
We already have a child, who was unplanned, although we were beginning to start talking about trying when we found out. It was the best thing to happen to us and we always talked about having more, but we've had a bumpy ride over the past few years and it was never spoken about again.
DD is now 7 and I can't help but think we need to make a decision as neither of us are getting any younger. I assumed DH had gone off the idea but when I was clearing some old toys out the other day, he told me to keep them in case we need them one day.