You might share the same vision with your business partner and along the line they adjust their vision to be slightly different from yours. They might start withdrawing their commitment, slack on fulfilling their responsibilities and lose communication with you. So then what do you do?

Humans are dynamic in nature. Their visions and ambitions can change anytime, I believe as a business person you should anticipate potential risk from any angle be it financially or your partner. Then have a thought out plan on how to adjust and run the business when a partner leaves before finding another one.