Either way, communicate! Put it all out there. If, even then, things don't seem like working out (i.e. the other 2 don't see a problem that needs solving), then leave.
As for what you do next, don't start a business for the sake of starting a business. Do it if you have a vision for what the world should look like. If you believe in the vision strongly enough, nothing can get in the way of you building the product/company to fulfill it. If not, don't fret. Working for a corporation is not the end of the world.
Find a place where you will learn something. There's a nice post by Garry Tan about learning vs. earning. Read it. http://blog.garrytan.com/lessons-from-2-5-that-i-wish-i-knew...