Partnerships can work if , like stated earlier, you can essentially be married to the person.
Ive partnered up with my brother in the past and it works out great, because we think alike. We can go into a job, and not say a word to each other as far as the work goes. We already know what each other will be doing next. Unfortunately, my brother hates this line of work.
We also live together, so its no big deal, really.
He is on his own now, actually partnered up with his girlfriend running a book selling business.
I remain on my own, and like it that way.