Initially, the client hired me for a project without mentioning any profit-sharing or assistance with commercialization. However, after investing approximately 30 hours into the project, I've produced a solution that far exceeds their expectations. Now, they're proposing a partnership where they would take 50% of the sales revenue and contribute to the selling process.
I currently possess the license for this solution. Throughout our collaboration, which has included three video calls (every call is free), the client insists that the time spent explaining their vision should be considered as sharing ideas with me. However, I have concerns that their involvement may be more of an opportunistic move, given that I've been working on a similar project for the past seven years.
I should add that the client is not fully open about what he wants in this regard. I am worried that he wants to clarify these new terms before he pays for the solution. He hinted that he probably wants a written contract.
Am I obliged to share the license and share profit under these new terms? Additionally, what potential issues could arise if I agree to share it?