Final answer:
The most enduring romantic relationships as adults are between individuals with a secure attachment style, which is formed in childhood when caregivers are consistently responsive to the child's needs.
Step-by-step explanation:
Researchers have found that the most enduring romantic relationships as adults are between individuals with a secure attachment style. In the context of attachment theory, secure attachment is characterized by the child using the parent as a secure base from which to explore the world. This attachment style continues into adulthood and leads to healthier, long-lasting romantic relationships.
A secure attachment style is established when the caregiver is responsive to the child's physical, social, and emotional needs, and the child and caregiver engage in mutually enjoyable interactions. In contrast, avoidant and anxious-ambivalent attachment styles, where the caregivers are either insensitive or inconsistently responsive, generally lead to less stable adult relationships. As a result, securely attached individuals are better able to form intimate relationships, avoiding feelings of loneliness and emotional isolation.