Being the head of the household is not all enforcing rules, providing structure, and disciplining your wife. While those are important parts of the role, they are far from the full scope.
Taking on the role requires a strong character, a strong sense of determination, strong shoulders (metaphorically), the ability to manage finances, a strong work ethic, courage, a good moral compass, the ability to plan strategically, leadership skills, and a basic understanding of psychology. If you are including a religious aspect to your relationship (e.g. Christian Domestic Discipline), a strong faith and willingness to humble yourself before God since you are taking on three responsibility for leading your family on their spiritual journey as well.
Beyond rules, structure, and discipline the HoH is responsible for providing for his family, protecting his family, ensuring they are heading in the right direction in life to provide the highest quality of life possible, ensuring all the bills are paid, making the important decisions, bearing the responsibility for any decisions made, and seeing to the health and well-being of the family, just to name a few things.
Each of these responsibilities requires one or more of the abilities mentioned above and it is imperative that you are able to fulfill them or you risk causing harm to your wife and/or marriage. Remember it is your job to lead.
For those times you need help, I have posted a prayer I wrote asking God for help in fulfilling my duties and to be a good Christian husband. You can find it here if you want.