What is the best way to split up the work? How can they share authority and responsibility?
Hire a Coach: A performance coach can help you set a vision, goals, strategies and tactics. Then they can work with you to prioritize the work and hold you accountable. A skilled coach will be able to push you and probe into the relationship when things aren't working and progress is not made. Many so-called life coaches can help with this. Think of it as a couples counselor and grade school teacher asking for a completed assignment rolled into one.