+100 I have had two business partnerships with a co-founder go south after a few years when personal situations changed drastically. With my first co-founder,

+100 I have had two business partnerships with a co-founder go south after a few years when personal situations changed drastically. With my first co-founder, it was when his wife was relegated to a wheelchair when an operation went wrong, and with the second, it was when her partner decided to end their long term relationship. NB: I wouldn't say that I was squeaky clean innocent either - in the first case above, I had also just gotten married about the same time, so it was the sudden change in goals and priorities for each of us that was the catalyst for the co-founder relationship to break down.