[mooreds]

For anyone else reading this, this situation is exactly why I recommend having these hard discussions before you write a single line of code. I did with the startup I co-founded. We essentially wrote up our "divorce papers" before we got "married". When it came time to leave, it was hard emotionally, but all the mechanics were laid out in writing.

We used the Nolo books (the partnership has a great chapter about how to handle the situation where a partner wants to leave, which is good for giving you ideas about how to handle things like ownership buy backs, if someone dies or is disabled, etc) and a good lawyer.

It feels risky to spend money doing this for something that is "just an idea" but don't forget you'll be spending your time (which is more precious than money) for months or years on this project too.

I realize this doesn't help the OP, but maybe it'll help some folks before they start working together.