Final answer:
The first stage a couple would normally experience in developing a romantic relationship is infatuation, characterized by passion without intimacy or commitment. As the relationship evolves, intimacy and commitment can develop, leading towards more mature forms of love.
Step-by-step explanation:
The stage one would normally expect a couple developing a romantic relationship to go through first is c) Infatuation. According to Sternberg's triangular theory of love, infatuation involves passion without intimacy or commitment, which is often the starting phase of a romantic relationship. This can be a period of intense, but short-lived, passion for another person. As relationships evolve, other components such as intimacy, which is the sharing of details and intimate thoughts and emotions, and commitment, which is the decision to stay together through various circumstances, become integrated, leading to more complex forms of love, such as romantic love or consummate love.
In the context of Erik Erikson's developmental stages, during early adulthood, people are primarily concerned with intimacy versus isolation and are ready to share their lives with others. A healthy sense of self formed in adolescence is essential for developing intimate relationships in adulthood. As stated by social exchange theory, the dynamics of costs and benefits also play a significant role in relationship satisfaction and longevity.