I hope you don't mind me butting in on your thread... I'm a WTTer and have just been nosing around in here haha. I read your thread with interest as I have always had a much higher sex drive than my husband. Throw in a little stress-related erectile dysfunction (which obviously then got worse and worse as he worried about it more) and we had a pretty rough time in our sex life for about two and a half years. However, these last 6 months or so we seem to be coming out of it so I thought you might like to hear what's worked for us.
Firstly (and I know it's SO hard) try not to lose your temper/get upset in the bedroom. By all means talk to him/argue with him about it later or tomorrow but try to keep the bedroom sexy. Reassure him, cuddle him, and don't make it seem like every time you go in for a cuddle you want it to result in sex (something I was guilty of... ooops). I think your idea about him associating sex with an angry woman was spot on, that's how my OH felt.
Secondly, don't let the laptop in the bedroom. It sounds like your schedule is going well but the problem with working from home is keeping work and home separate. Me and my OH both work from home and we've found it really difficult at times - if we're having a bit of a lazy day at the weekend or something we might have our laptops on our laps in bed, answering emails and things - but when it comes to bedtime we can't switch off enough to go to sleep, never mind anything else! If it really is impossible to ban it from the bedroom completely I think your idea of at least stopping him opening any work related programs is the best bet.
Thirdly - make lots of time for just the two of you but without the pressure of sex. Spend the whole weekend naked in bed watching films, cook together, read or do whatever else you enjoy in bed together. I definitely found the less I pressured my OH the more he seemed to want to do it (it does sound like this may not work with your OH but it's worth a try. And as previous posters have said intimacy is about more than sex so you never know, you may have a great weekend even without making any progress sex-wise).
Finally, yes we have experience with Maca. I put him on Wellman Conception two weeks ago (as they advise taking it for 3months before TTC) so that's been 250mg of Maca daily and I don't know if it's just coincidence but it really does seem to have helped. TMI - yesterday we DTD twice in a row and that hasn't happened for years!! I might keep him on these supplements even when we're not TTC haha.
One last thing - have you thought about the fact that maybe your OH has depression? The lack of interest in sex, the zoning off when you're talking to him, the defensiveness... all could be signs. If he doesn't talk about his feelings I'm not sure where a diagnosis would even get you but it's worth thinking about.
Sorry to have written an essay, it's just your story really struck a chord with me. I've spent many a night crying myself to sleep and wondering when it comes to TTC, how on earth are we going to manage because we simply didn't do it enough. But things are most definitely looking up

I wish you the very best of luck