This, seriously. The reality is that you're leaving a company that has /no value/. It may have a number of pieces to get to value, but you're nowhere yet. Sometime, in the future, some set of pieces may come together that will give this company value; but they don't exist now.
( When I say value, I don't just mean profit; if you can't merge with another company in the space, or sell your code to another company in the space... No value.)
If it's just time and sweat to get to value, then don't leave! Take a vacation. Come back ready to make it work.
If it's time and sweat + some set of technology and business process innovations = value, then allow the cofounder who sticks with it to reap their reward, while you reap a different reward for different work.
> The reality is that you're leaving a company that has /no value/
From the sound of it, that's probably not even true...the company actually has negative value. The seed money wasn't given as investment, it was a loan. It doesn't sound like they've been able to create $10k of value to offset the liability of the loan. If the poster is able to walk away without having to pay back their share of that loan, they should probably count themselves lucky.
( When I say value, I don't just mean profit; if you can't merge with another company in the space, or sell your code to another company in the space... No value.)
If it's just time and sweat to get to value, then don't leave! Take a vacation. Come back ready to make it work.
If it's time and sweat + some set of technology and business process innovations = value, then allow the cofounder who sticks with it to reap their reward, while you reap a different reward for different work.