I did something similar... with my ex... no wait a minute, I gifted a 1/2 share and she didn't even work in the business!
But seriously, it depends what you are trying to achieve. In my case it was common for income splitting.
If you are after some extra ready cash it could be a good idea. Similarly, it could be a way to let your key staff become more involved and committed in the business.
On the flip side, you may loose control of some key decision making and direction of the business depending on how much you sell and what your new partners role is in the business.
I know of a few cases of partnerships where one partner, for one reason or another wanted to change direction in life and sell their business interest. The other partner was in a position of intimately knowing the workings and profitability of the business and was able to buy out the other share making exiting the business a much simpler option than putting it on the market for example.