the family unit will be less vulnerable when there is a spouse with a consistent, separate flow of income

We have emotions, preconceived notions and biases, and not all decisions can be made by consensus. 

It is much easier to focus on the role of husband, wife, father, mother if work conversations are kept separate

the family-focused spouse may begin to criticize the business-focused spouse while the business-focused spouse may begin to resent the lack of perceived support for the venture

Often the ability to express your feelings and be reassured of your personal worth and the unconditional love of another human is what is needed to be able to continue to function in the work setting