So if you're saying that they need you for another 3-6 months, then it might be worth pushing forward exit talks now - before you become useless and unnecessary in the business, and while they need you.

Your lawyer will be able to advise you on strategy here, and if they're cool-headed, it might be best to get them to negotiate on your behalf. (I know personally, one harsh comment or unfair criticism and I'd lose my focus in negotiations, or break down and be unable to cope. So having an experienced advocate might be worthwhile.)

How I would be playing this would be:

a) I'd explore a scenario where I stayed on in a non-tech role, without losing the equity vested.

b) I'd explore whether I could (kindly) stay on for the 3-6 months they needed in return to receiving a payout for the equity vested at an agreed amount that saw me take back the personal wealth plus an agreed amount of money for the vested equity. (This is going to hurt, and you'll feel like they paid too little while they feel they paid too much, but I don't think you should tie your equity to something illiquid that you have no control over.)

c) I'd explore plan b, paid out over instalments instead of in one lump sump, if they don't have the capacity to pay right now.

d) I'd explore plan b as a mix of equity plus cash - maximising cash.

e) I'd explore plan b, but instead of a payout I'd look to increase the vested equity in the company to an agreed amount. (If they can't get the money to pay out out now, this might be the only option - but I think it's messy and risky.)

f) If you can't get any of those, just do whatever you can to walk away with as much of the capital you've invested as you can - ideally in cash.

How did things work out for me?

I ended up with a Plan C. It worked out to be the equivalent of about 1.5 years dividends from my shareholding as we were structured differently, was already profitable and industry-leading in what it was doing. I thought I got screwed. My co-founders thought they paid too much. Whatever. All divorces are acrimonious.

Fast forward a few years, and I have a new company that makes me more money, sees me working 10-20 hours a week, and doing something I enjoy doing far more.

What's happened to my co-founders? Well, the business reached saturation point soon after I left, and is now struggling to survive. After we finally forgave each other, I caught up with my now greying, stressed, sick, tired, overworked and underpaid cofounder/former best friend and I feel sorry for him. He actually looks at my life now and envies it. :(

What happened to me at the time left me teetering on the edge of suicide. It was humiliating. It was a huge fall from grace. And I felt utterly destroyed: financially, emotionally, spiritually, and physically.

It took me 18 months to recover, 2.5 years to regain a level of confidence in who I am and what I do, and 3 years to build my new business, and 4 years to stop regretting what happened and feel happier about where I'm going than where I've been.

You sound like a smart guy - and I'm confident that your new life will be far better than the hell or uncertainty you're in right now (or the hell you may be in for another 3-6+ months).

My wish for you is that you get to leave your current situation with the best possible foundation (whatever it looks like) and you begin your new life as soon as possible.

If your future isn't in this venture, then the sooner you get started on "the next thing", the sooner you'll get there.