Final answer:
Commitment is the key element for maintaining long-term love according to Sternberg's Triangular Theory of Love, and is a part of consummate love.
Step-by-step explanation:
According to Sternberg's Triangular Theory of Love, the determination to maintain long-term love is characterized by commitment. Commitment alongside intimacy and passion forms what is known as consummate love, which is considered an ideal type of love for long-lasting relationships. Examples of relationships that fit different types of love according to Sternberg's theory include companionate love, often found in close friendships and family relationships, which is defined by intimacy and commitment but no passion, and romantic love, which has passion and intimacy but lacks commitment.