It's not a fault thing. You both went into the marriage and into parenthood of the 2 DC you have, knowing that you both wanted different things. That's equally on both of you.
You can only decide for yourself - do you want the family you have more, or the possibility of more children more, with your existing family looking different?
You can't decide for your DH, and likewise, he doesn't have the power/right to stop you from leaving if that's genuinely what you want. It's not his decision of no more children, or your decision that you can't live without the possibility of more children which would "break up the family", but your mutual incompatibility.
Stop blaming each other and feeling resentful, figure out what you each actually want and work out a way forward. Maybe relationship counselling would be helpful?
For example, maybe DH would feel open to another DC in a few years' time, with a larger gap - you could look at a long acting contraception yourself (or vasectomy reversal). Perhaps you would get the busy home/big family feel you want by pursuing a career where you work closely with children over several years, developing relationships with them, or by pursuing close relationships with cousins or DC's friends and inviting them round frequently so it feels almost like a "second home". Perhaps (if DH on board) you could look into short term fostering or hosting students or childminding, if it's more that you like the idea of a "full house". Perhaps pets could fill a similar sort of role. Maybe you could co-parent amicably but have further DC by IVF and sperm donation.
Thought experiment: How would DH feel if you stayed together and did not TTC but got pregnant accidentally? How would you feel if you split up and you never meet anybody else/never end up having more DC?
Yes, some of these suggestions are bizarre or extreme or probably don't work, it's just ideas to mull over and really think through the whole scenario.