You also need to realize that should anything successful come out of the startup your contribution will be almost negligible compared to all of the work that go

You also need to realize that should anything successful come out of the startup your contribution will be almost negligible compared to all of the work that goes in from this point. I had an amiable co-founder breakup, and he still has a percentage of the company, but every day the proportion of the work that was done with that former co-founder grows smaller. We're kind of the same idea, but definitely not the same product, about 10 iterations further, an entire team of people who have been working nonstop for a year, millions of dollars of money risked, etc. I still am grateful for the work he put in, but it's now a tiny, tiny piece of the overall puzzle... It just takes so much to be successful that the "idea" can't be worth much. I still plan on hooking my former cofounder up if/when we have an exit, but recognize that if you take a large percentage it will make every aspect of the company incredibly difficult, especially when it comes to fundraising.