First, congrats! It is a great achievement to have (effectively) single-handedly built your first startup. If you're going to break-up, try and get what you ca

First, congrats! It is a great achievement to have (effectively) single-handedly built your first startup. If you're going to break-up, try and get what you can out of it. I don't think you should get lawyers or courts involved -- wait until there is real money (if ever) before taking that plunge. Instead, why don't you offer to have your co-founder buy you out? I don't know what you'd charge for contracting, but 1200 * 150 = 180k. If you make that a debt that he owes you due on a liquidity event in exchange for him having total ownership, then you walk away with nothing now (which is the most likely outcome regardless) but you do have recourse if he ever does hit it big. It is also the best deal for him, as there is a working and near-done system that he can effectively get for free -- if he has a big liquidity event, then he should be happy to pay you a decent contractor's rate. Write something simple up in plain english and include a note where you agree to binding arbitration, which should save you both some cash if you ever have a deep disagreement in the future.