If we start a business together, let's set up a small company, a small shop or something, start a business together, have a sense of accomplishment and want to support each other.
If it's just to spend more time together, in fact, as long as it's not a frequent business trip, it's no problem to be too busy to lift your head.
However, I personally suggest that the two should not be together, because reality has proved that unless they are both open-minded, there will be bad blood.