As a 4x founder myself (serial, not asynchronous), I don't think the concept of a "portfolio" entrepreneur is necessarily bad. However, if Mr. X is directly blo

As a 4x founder myself (serial, not asynchronous), I don't think the concept of a "portfolio" entrepreneur is necessarily bad. However, if Mr. X is directly blocking progress then that is a problem. If you aren't being paid, that is also a bit worrisome. If he has a good track record, I am surprised he doesn't have seed money already to fund him at the idea stage. Another red flag would be if you and Mr. Y didn't really know or interact with Mr. X previously. Usually, successful entrepreneurs have fairly good network of resources and often times work with people they might have worked with before. Just saying they red flags and you may want to be cautious about how successful he may appear vs reality. Is it possible you can bring someone else on that can do his role? Does he have a vesting cliff for his own equity? How is the company formed regarding voting rights? Does the company own the IP? If you and Mr. Y effectively have 60% voting to his 40%, and he is vesting, you should be able to remove him and use his un-vested equity to bring in someone else. If you don't have a company formed with proper stock/voting/vesting/ip assignments in place, then I would immediately stop until this is done. You have very little legal recourse. This is were co-founders get into huge legal problems later on. This should be a non-starter. You should immediately make claims on any IP you have committed if there is no agreement in place. The biggest misconception is that ideas are worth something. They really are worthless. Execution is everything. Good ideas fail all the time. When two companies with the same idea compete, the one that executes better, mostly will win. It is a huge risk to quit your day job to work on a project like this full-time. My last recommendation is to search internally for why you joined this team? Maybe it was exciting to be doing your own startup, or maybe you felt it would be easy with Mr. X to get funding. But startups are incredibly hard and 9/10 fail. So you should make sure that you honestly believe that the product/service is valuable and that this team can iterate it to market.