Your hubby's reasons for not wanting more kids are all logical, fact-based, and true. Your emotional reasons for wanting more children are emotionally-based, and in their separate arena, also true.
It sounds like the problems you have in talking through this issue are based on the simple fact that your arguments are coming from two different "realities," neither of which includes the other.
There are a variety of approaches you could use to address the communication blockage. These might include counseling, or looking into a process like Non Violent Communication.
Be aware that if any such approach is to actually work, though, both of you must be open to the possibility, somewhere in your souls, to see the other's point of view and find agreement. That could mean your husband eventually embraces the idea of another child (or two), or that you embrace the idea of being blessed and satisfied with the two you have.
Your "desperation" is important to take notice of. Desperation is a word properly applied to the basics of physical survival: air, water, food, rest, bodily protection / shelter. A sense of desperation for children is possibly a signal that some deeper soul need is going unsatisfied.
If your husband can never find the assurance in himself that he can deal with the awesome responsibilities of bringing more babies into his family, it may still be possible for you to identify your deeper desires and satisfy them in some way that will not undermine your union with your spouse, or his ability to meet your family's most basic needs. Blessings to you both as you work your ways through this difficulty.