Why did Ashley Wilkes marry Melanie?

Ashley Wilkes married Melanie Hamilton primarily due to societal expectations and familial pressure. He felt a sense of duty to fulfill his family's wishes and believed that marrying Melanie, who embodied the ideal Southern belle, would align with those expectations. Despite his deep feelings for Scarlett O'Hara, Ashley's decision was influenced by his desire for stability and the traditional values of the time. Ultimately, his choice reflects the complexities of love and duty in the context of the Civil War-era South.