I started a little company in my city with what I believed was a close friend. I had a job and I was still at university, while he didn't and had a wife and a newborn daughter, so I thought he was committed enough. I was wrong because he had backing from his parents that are quite wealthy.
After some months in which I was the only one that made some work (website design), bringing some money in the company while he was losing time with the excuses like "I'm not ready and I don't want to ruin the company reputation (he was the sales guy), he decided that it was better to split our paths. I "sold" my part of the company to him and after one year he closed it full of debts.
From then on I always found myself in a better position doing things alone. They say that the weight is to much to endure for one single founder, but I don't think so. I was always able to endure everything. If you have friends or relatives or a partner in your life, you are never alone. If you need their support, it does not matter if they are in your venture or not.