By divine design, fathers are to preside over their families in love and righteousness and are responsible to provide the necessities of life and protection for their families. Mothers are primarily responsible for the nurture of their children. In these sacred responsibilities, fathers and mothers are obligated to help one another as equal partners. Disability, death, or other circumstances may necessitate individual adaptation. Extended families should lend support when needed.
The Family, A Proclamation to the World, paragraph 7, last half.
Importantly, Mothers and Fathers each have separate and specific stewardships. Perhaps even more importantly, we are obligated to help each other as "equal partners" in carrying out our stewardships. This could simply mean that we let an awareness of our spouse's stewardship inform our own actions as we fulfill ours. We reflect on our own helpfulness thus far, find out how we can continue to be helpful, and follow up to see that we actually are being helpful.
Individual adaptation and help from extended family are merciful, necessary provisions inherent to our struggles to implement this divine design in mortality, which can get messy.
For example, when near the end of his mortal life the Savior instigated a truly thoughtful adaptation for his family when he said to one of his disciples: "Behold thy mother! And from that hour that disciple took [Mary, Jesus' mother] unto his own home." (John 19:27)
Elder Richard G. Scott taught about the Ammonites in the Book of Mormon who found themselves in a situation where fulfilling their stewardship of protecting their families would have violated a special covenant of peace they had made earlier. Fortunately, that covenant facilitated the spiritual nurturing of their children, the stripling warriers, who enlisted themselves in place of their fathers as protectors of their families by going to war at a desparate time.
The phrase "divine design" wasn't inserted just for its aliterative and rhyming rhetorical effect (although Neal A. Maxwell, a master of rhetoric helped craft the proclamation). "Divine design" is synonymous with "family", or stated another way the family is God's divine design. Software projects are often born of some kind of "design document", which details the purpose, structure, and function of the end product. Let's think of this proclamation then as a "divine design" document. Consider the end product resulting from universal acceptance and implementation of the purpose, structure and function of families as explained in this proclamation!
The very good news is that Fathers presiding, providing, and protecting, mothers nurturing, parents helping as equal partners--this description of the ideal, if not yet reality, will become so for all the faithful. In the August 2016 Ensign article by President Eyring he mentioned a time when he worried that "the choices of others might make it impossible for [his] family to be together forever". The prophet at the time reassured him: "You just live worthy of the celestial kingdom, and the family arrangements will be more wonderful than you can imagine."