It's funny how people who don't know history seem to be doomed to repeat it, right? In our young age we might bunk in an apartment with a friend, only to realize that despite being awesome to hang out with, that person is an absolute mess that you couldn't live along with. Extend this comparison where the stakes are raised and you have a recipe for disaster.
Then again, communication is key : we often don't communicate enough because we believe what we need/want is clearly implied when it isn't, or just being judged for communicating. Well, in couples or in business, overcommunication rarely leads to fallouts like undercommunicating.
RE: Alternatives to getting into business with friends, spouse, or relatives when founding a Startup