Thing is, when you’ve had a third what if you’re desperately craving a fourth? Where does it end?
Is your house rented or owned? Is there a fourth empty bedroom for a new baby to have their own room?
Ultimately, having a child (whether first or tenth) has to be a ‘two yeses’ decision, the person who doesn’t consent to another child always has to take presedence as the alternative is bringing a child into the world one parent didn’t want. Which is an awful thing to knowingly choose.
I think most people would be with your DH in thinking two is plenty, count your blessings etc. but what matters is how the two of you feel. Put bluntly you have choices here:
Accept you’re sticking with two and work, really genuinely in good faith work, to come to terms with and accept that
Decide you can handle waiting a few years and revisiting the decision, with the knowledge that his answer may still be the same
End the marriage so you can pursue having more kids with someone else or alone
Those are your options. Note none of them are ‘cajole or try convince DH into a third/have an ‘accidental pregnancy’, hold it over him and damage your marriage in the process.
What do you plan to do?