One relevant question is, is this actually a company already, with incorporation and ownership. Or is this just a side project so far. Another big question is,

One relevant question is, is this actually a company already, with incorporation and ownership. Or is this just a side project so far. Another big question is, does the co-founder bring anything tangible to the table. Do they have an online following, sales/marketing connections, experience building a business. Really you do want someone who is an equal partner, who's value makes the pie bigger. If you can find such a person, they are totally worth 50% equity (actually slightly less, since you want a third minority owner to act as a tie-breaker.). But the only way to really vet such a person is to see them in action, which requires them to volunteer at first probably. Maybe you could work out a commission deal for revenue share. That allows you to motivate a partner simply, without selling off equity. (Remember giving away equity also costs money in lawyer fees).