MTV, this really struck a chord for me:
I had pnd and didnt always want sex but he never went without for more than 3 or 4 weeks. Was also on prozac which diminished libido. Told me a few years back that he woukdnt touch me again (he was hurt being rebuffed). Has stuck to his guns pretty well since then. Guess he must only have come near me around a dozen or so times and I have not refused him once. However, I have never initiated anything with him first as he was the one who took his love away and closed down and I cant see through that.
It sounds like he perceives that you were the one who "took your love away and closed down", by reducing your sex life and rebuffing him. I'm not saying that's how it is, just that people in a relationship can perceive these things very differently from each other. It can be so difficult after childbirth because all the little routines and patterns that a couple know about each other get thrown up in the air. If there's a period of no or not much sex, it can be really hard to get back to feeling easy and spontaneous about who initiates what, under what circumstances you can push, how to read what the other really wants etc. etc.
But if his experience is anything like mine, I think the main thing could be an issue of change in what sex represents, and the power dynamics around it. I say this because you say he "never had to go without..." and it sounds very much like sex became something you gave him, or did FOR him, rather than something that served your own pleasure just as well.
This may not be your fault - it may even be his. But the point is it changes EVERYTHING. When two people have sex because the both want to HAVE SEX, and they are both satisfied by it, then it is a closed episode and neither "owes" the other anything. When they have sex because one wants it and the other is "prepared to give it", then it potentially isn't. A huge bloody great question mark can develop around what exactly they're giving it for, what they expect in return etc. etc.
This can unfortunately make a man feel like sex is the payment he gets for being a good little husband and meeting at least some of the extra expectations that come from having a family. Which, regardless of whether it's justified or which party is responsible, can be a HUGE turn-off. What was once a mutually satisfying shared experience is now a contract he finds himself signed up to, without knowing exactly what price he's agreed to pay for it. And he can respond by effectively saying "fuck you, you can keep your sex".
That's a bit how it was for us, anyway, although thankfully we found our way back from there. YMMV.
[NB: I have to say, I reckon if he can't go 3 or 4 weeks without taking it personally, he's got a pretty woeful idea of the realities of family and child rearing. But that's probably not the point, the point is how it felt from his POV. Probably depends how long it went on like that for, too.]