OK, so does she want more kids or does the thought of it fill her with abject horror.
If so, how about discussing a vasectomy. If your family is complete, if your wife has had a difficult pregnancy and birth, and has carried 2 children in a relatively short time, perhaps its time for you to do your bit to ensure she at least feels safe regarding pregnancy if your sex life is to resume.
Does she plan to go back to work?
You will be surprised exactly how totally worthless and undervalued you feel as a mother, how being a mother and housewife (because it doesnt pay a wage, and nowdays paying a wage and fulfilling your tax obligation seems to be ALL that matters) it can make you really go adrift. as if you have literally disappeared as a woman, as a professional. And I would imagine that if she has come from a city job then the 'fall' would be even greater. It can jar all your previous thoughts about equality and throw up thoughts about her own childhood, about her own insecurities and also the fact that all her education, academia and career to date means buck shit and she is basically doing the same job, and struggling as its so exhausting, as every other woman the world over. Motherhood can be a transformational and very difficult emotional time even in the best of circumstances. And she is doing this practically single handed.
The rule of thumb on MN seems to be equal time off. Does she get equal free time as you? You say you are reasonably well off. Why not get a cleaner/home help in. If she wants to look after the babies then fair enough, free her up from the housework and some of the cooking. Appreciate what you are getting from her rather than what you are not.