Many years ago, I heard the story of a man whose business partner did dirty. They were business partners for almost 5 years and the suddenly the business partner left with company's money. Even after several years, this man didn't recovered. He ended up sounding it as a warning to his kids never to go into business with anyone. The trust was destroyed and never recovered. This is just one of those sad stories.
On the other hand, there are many success stories of friends who went into business together and succeeded to together. If you have ever gone into business with a friend, what were your biggest concerns and how did work through it.
Money spoils people, that's a sad truth... Many successful business projects were launched by a small team, sometimes even by only two friends. And when the project becomes profitable, conflicts emerge. Often former partners start sueing each other, splitting business etc. And if someone wants the great deal of money, then he/she should do the best to successfully beat the former friend, and take the whole business initiative under own control. Nearly all biographies of well-known entrepreneurs contain such steps on the way to money and fame.