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.
Something that is difficult to build in a business partnership is mutual trust. Trust will be established only with friendship. However, suspicions began to arise when the business that had been built was successful, and at certain times the income was not as good as usual. There is no other solution except to get rid of all bad prejudice to our business partners. However, if business partners have the intention to cheat as you describe, of course they have chosen the wrong friends from the start.
But we shouldn't feel down after such conditions occur, because they will feel proud to tell others when something bad happens to us. We have to be able to get up and start a new business until it's successful, and people who deceive us will feel guilty when they decide not to cooperate, or commit fraud.