Hmmm, I have never been in this situation. My DH was on board with TTC again in the first place and then has been there with me for the 4 miscarriages ride. He is still okay with us trying, even though I have been psycho all summer
I would say, in this case, back off for a couple months. As much as you might want to push him to TTC, I would gather he needs a little time to let things calm down and then make your case again. Simply and gently (that you realize now, more than ever, you do want a third child and would like to do so as soon as he is ready) and then leave him to think on it again. You might be surprised and he will okay it right away, having been given time and space to deal with the loss. Or he might need another couple months.
I am of the mind that it never helps to "dwell" on it. That never seems to help anyone. I would try to enjoy this quieter time and then bring it back up. So sorry you are having to go through this. It is not something we would wish on anyone