It's a nightmare scenario. If it was me I would play hardball back. Walk away from the whole thing and let the company melt down, better that all should lose than he should win and all you should lose. Alternatively maybe he comes to his senses, but you have to be willing to carry through with it. I hate playing hard ball, but once you find yourself with someone who is going to do that, you have to play hard ball back or you'll lose for sure.
If you do decide it is all for naught and you are probably going to bail, I recommend you open source your code base for some plausible business reason, and then wait a few months before leaving. This way you'll be able to recover your own work for use in future ventures should it come to that.
Obviously you picked the wrong VC but why on earth would you give him such veto power. That was your mistake and now you are paying the price. Oh well.