Nicole and Matthew, a couple, are passionately in love with each other. They are attracted to each other and also share their thoughts and emotions. They are thinking of a future together and know that they can depend on each other even in the face of problems. According to Robert J. Sternberg's triarchic theory of love, Nicole and Matthew are most likely experiencing

Nicole and Matthew are most likely experiencing the decision/commitment component of love.

According to Sternberg's triangular theory, the three component of love are:

intimacy, which is the feeling of familiarity, of bonding and being connected; passion, which is enthusiasm and mutual attraction; and decision/commitment, which is the realization that you are in love and the will to maintain this state.

We are told that Nicole and Matthew are already past the intimacy component because they "share their thoughts and emotions," and passion has been established as well: "they are attracted to each other." The important element here is their willingness to plan "a future together" and to assist "each other even in the face of problems." This stage shows a conscious desire to take binding decisions, which is characteristic of the decision/commitment component of love in Sternberg's theory.