1.) Talk to your cofounder. 2.) Hope that he/she is willing to give up their share and leave amicably. 3.) If he/she is willing to give up their share and lea

1.) Talk to your cofounder. 2.) Hope that he/she is willing to give up their share and leave amicably. 3.) If he/she is willing to give up their share and leave amicably, get a lawyer involved. You should pay for this. He/she may want to get a lawyer involved too. 4.) Be prepared to abandon the idea and all the work you did. 5.) Learn from the failure. --- Here is the issue. You have created a situation where your cofounder has all the power. Without any other agreements, you have to assume you are equal partners. Even if he/she leaves amicably, they can always wait. If your startup succeeds, it won't be hard to find a lawyer who will go at you for a percentage of the settlement. If a lawyer goes after you, you should assume that you're fucked, as fighting it will create such a distraction that your company will likely die anyways. If you can negotiate some kind of pay for work scheme, then incorporate, you might be okay. But, there is a huge power imbalance right now. Do you have any other ideas??