Mutatio, you know I am in the same situation. In the last month or so my H has been initiating conversations a little bit. Not every day, and there is no warmth or seeming genuineness to it, but still it is there.
I can't say for sure, and I definitely can't say this would apply in your sitch, but I think for us the turning point was in the beginning of September we had a discussion where he told me that I had been so unwelcoming to his visiting parents that they cut there trip early and left without saying goodbye. I had done nothing wrong. When he told me this, I told him - and I was not bluffing- that this was as good as I could be with his parents, that I had done nothing wrong, and that his anger and his attitude towards me were at the point that I thought he should consider moving out. It was a calm (ok, calmer than usual) "I am willing to let you go rather than take this treatment anymore." From that point on, I noticed he has been "trying" - not well, not with warmth, almost like he is reciting a script that I am pretty sure he worked out with his IC. Things like "How was your day? What else did you do? " and most recently he asked me if I would like to go to dinner with him in 3 weeks from now (WTF?????) There are still some days where all I get is a "hello" and "good night", but while he was on his most recent trip (10 days) he texted me daily and even called me most days. I think he is thawing. Today is the first day that I can honestly say some of his interactions seemed natural and not "scripted" or forced. (although still not warm.)
So. Again, might have nothing to do with you. And I might be reading my own situation incorrectly, but I think the thought that I was willing to let him go made a difference to him. I also brought it up again in MC in the context of he is adding stress to the whole family with his angry and withdrawn attitude. And again, for all I know he could slap me with D papers on Monday, he still isn't having conversations with me so I don't really know what is going on with him. But it seems like the ice is melting slightly. I wanted to just share my sitch with you in the event it can give you some hope or something to think about.
In the meantime I have been perfecting the art of not reacting and validation, and asking him open-ended questions about his work. I *think* it is working. But its a very slow process and I am trying not to get too hopeful.
