Totally agree with @ScreamingLadySutch
Far too many people being completely unreasonable in their responses. Berating OP because they have a definition of what "NC" is, and as it's not being met, in their eyes, they have to swan in and 'correct' OP. The reality is, OP and her husband are human. That means you experience emotions, such as guilt. How many times have any of us been friendly with someone, they've wronged us, but you've ended up feeling guilty about something and re-establishing contact to try and remedy it? I'd be more concerned I'd married a psychopath if he could go NC with his family and never feel any emotions regarding them again. It would be robotic, and incredibly unnatural, behaviour.
OP, please don't feel like you need to justify yourself to these people. I'd imagine most of them have never had any real, challenging familial relationships, and so can't understand the complexities of the issue. I'm glad you and your son are NC with them; I read your other threads and was genuinely appalled at your MIL's behaviour.
You acknowledge that it's trickier for your husband, and I think he's doing the best he can, at the minute, with the situation. It'll take time (and by time, I think years rather than days or months) for those guilty feelings to fade. People here forget that he's had to live with her manipulation for a lifetime. It's very hard to switch off your natural reactions to someone who has made his life all about her.
It's quite funny, really. Mumsnet is the place where most things are a 'DH' problem, he should do this, he should do that. Yet here's a man who actually has cut contact. He's married the woman he loves despite knowing that it wouldn't go well with his family because of their issues. Yet, because he has went to tell them in person (which IMO isn't stirring up drama, it's just a natural response to years of dealing with overbearing, controlling people), OP is loving the drama? If OP loved the drama as much as posters let on, why would she go limited/NC? Surely she'd keep them in her life so she could rant about it every week?
I think some people are simply jealous that OP has had the strength to do what a lot of people wish they, quite simply, had the balls to do themselves.