Two heads are generally better than one. And three heads seems like an even better idea. Not to mention 4 or 5. When it comes to startups, partnering with another business/technology enthusiast such as yourself might seem like a must-do. However, a wrong decision in this department could cost you your start-up.
If we look on the bright side, business partnerships mean burden sharing, mutual support, companionship and problem sharing. It is something like a mix between a shoulder to cry on when things go wrong and someone to hug when things go right. On the dark side, it also means less autonomy, not being able to do what you want all the time, slower decision making and often fights about everything.