There is a damn difference between someone who throws an idea at you and walks away for a couple of months until you finish and someone who has a really a good idea yet he is totally dedicated and working side-by-side with you for the product to work, also willing to learn anything in order to help the company grow.
Why do you complain about the percentage?You want 100% or 120%?Come on!If he is not dedicated at all you don't work with him otherwise don't complain.Not to mention that you want to take the idea and walk away with it!So this is not a shitty idea then.Yet again, you want more and more %.
You need to understand that the execution of the idea is definitely important but if you don't have it, there is nothing to execute, ok?The road is idea>execution>business not execution>idea>business etc.So no (great) idea = no execution, no execution = no business.Either way, you must have an idea to start with.Besides, we don't know the real story.Maybe he asks for 50% so you don't eff him up later on and you showed us you are capable of many things.I wouldn't work with you if you ask me. You're money driven not passion driven.
There is no "Zuckerberg Dilemma".Mark stole the idea and improved it in time.