Being in the family business for so long, I often ask myself this question. And debated with many people about it too.
Most people think: Of cos it's good! Couple should strive it out together (in this case, doing business) and they have more topics to talk about.
Not more conflicts and arguments meh?
I always see my parents having cold wars due to different views and ways of handling things.
And hor, you cannot really concentrate and chiong all the way, unless your partner is those cannot be bothered at all. You will have to consider his/her feeling and sacrifice alot in order not to make him/her unhappy.
On the other party side:
It's really not easy unless you have super high tolerance towards bitch and bastard.
In a normal way, it's not wrong for you to be angry or upset. But in a professional way, you will seem very immature. You will contradict yourself between your feeling and mind.
All in all, I still feel that it's not that nice to work together. You will unknowingly be a hindrance to each other.