Speaking as a business guy, my default position is to be turned off by co-founding with a technical guy unless they have an amazing track record. I like the advice of earning a business co-founder.
I just wish more technical guys realized their code isn't that special, isn't a magic way of printing money and just coming up with the implementation doesn't entitle you to 75% of a two-man venture. It doesn't even really entitle you to an extra 10%.
In the beginning, your job is probably going to be to find a place to host, writing alpha CRUD apps, buying computers, buying food, buying and assembling furniture and generally just making things work. That's all very unglamorous work but, depending on the venture, it's quite likely your (alleged) coding skills will be of very little value (until you've found a market).
I don't think I'm alone (as a business guy) in generally finding technical guys to have an inflated sense of self-importance who often want to treat business people as an exchangeable/replaceable commodity.
The difference in results across two developers can be incredibly pronounced; sometimes, those egos are very much earned.
Personally, I started a company without a business guy and no external funding. It was incredibly difficult to do without external capital, but we own it, and we're not beholden to external interests. We've hit a million a year in revenue, and are poised to completely eclipse that. I've had to step up to effectively serve as CEO and CTO, but without the code, there'd be nothing to sell.
I'm not claiming that 'business' doesn't matter, but rather, that compared to the people that imagine and then create the things you're going to sell, the usual business guy -- minus any other specific skills in the field in which he's working -- is a commodity.