Competence is defined in the dictionary as "the ability to do something successfully or efficiently." It is a character trait and virtue that you want when you see yourself desiring to get to a goal quickly and with the least waste of resources, which is efficiency. Competence is a combination of the Skill of Collaboration with the trait (or Commonality) of Intelligence.
We finally move from a focus on each other, and the actions of teamwork, to a new alignment with each other that has us turning outward at the world, our contribution to it, and rewards as a couple, from it. We are unified and focused on both our contribution to it, and the rewards of meeting our goals in it, through the Virtues of Collaboration as a skill of commitment.
What makes Competence unique as a character virtue, is that it addresses the focus on getting to a goal efficiently, which also assumes the mature, realistic expectation of some "trial and error," or "a learning curve." One or the other partner may even have to make a major sacrifice to the relationship, itself, just to learn a necessary lesson.
We see this often in such metaphors as a mountain climbing expedition, where a major expenditure of time might be lost, such as trying to summit Mt Everest and finding that we have to turn back and give up until the following year. It just isn't safe.
Or when a partner bites off more than they can chew in a new job opportunity, having to double back to a job they don't like, to save the family finances, or to keep the other partner happy on their particular path. Yet, there is an expectation of a gain in competence for so doing - the price we often pay for new education or experience being, "time." Whether in the form of having to go back to school for four whole years without one of two major incomes, or simply having to save for longer to take the next, educational vacation, we expect as a couple or a family to be even better for the personal sacrifice of new, perpetually useful knowledge and maturity.
From Aristotle's Golden Mean, we learn that every virtue also has two vices. In the case of Competence, the vice of excess is Usurpation, or "self-nomination," like crowning one's self, King or Queen. This also calls to mind that the King or Queen personality style - being one that lends itself so much to all things analytical and intellectual - is a good fit for the character trait of Competence. And so their darker side is one of being "snooty" or "Holier than Thou," assuming leadership as a given rather than being voted into leadership of something by your partner.
The vice of deficit for Competence is called, "Charlatanry," which is an easy opposite to understand: rather than being VERY gifted at something and making an assumption of leadership, one's pathological narcissism is facilitated by the "potential to learn" in a sharp, inborn, left-brained analytical mind, but in absence of actual education or competence sometimes seen in Lover or King/Queen personalities.
When it comes to life's goals and your dreams, it doesn't make for a good teammate to have "self-nomination to leadership" in a partner - bossiness - nor to have Charlatanry in a partner.
Usurpation toward a potential partner is similar to the common phrase that partners say: "She crowned herself, Princess." Or "He acts like he's all that, and assumed I'd just move to the new city and his new job with him," or in the case of Charlatanry, my boyfriend/girlfriend/spouse "Had me being the blind, following the blind."
These features show the vice in some relationships that pertain to the deep nature of how commitment and partnership really are a team approach, and even of the many ways that modern couples tend to ignore or violate their own marriage vows - "to join the two, as one," rather than go to their goals in separate corners of the house, and "adhere to each other in good times and bad," rather than only when it's convenient.
We might often see a couple have a falling out, because they can see, hear and feel the deep level of disempowerment for either gender in "self-nominated leadership" or Charlatanry as vices, when instead, we needed their Competence (or potential for growing it) as a virtue - something that can only come from a mature, constructive place, characterized by a "win/win" actions toward real intimacy in the partnership. Intimacy that is not just sexual or honest, but actually joins them in action toward goals.
Competence has bearing on our performance in phase three - intellectual attraction - step eight, where we seek to amplify the best virtues toward our goals. It is what causes us to see our mate as "knowledgeable" in our lives, and us to feel that we will have losses, but will have more gains that losses with them.