Cunning Single Lady (2014)

Na Ae Ra is the prettiest girl in her town. Many guys around her try to win her heart but she dreams of marrying a civil servant. One day, she meets dorky Cha Jung Woo who is preparing for civil service exams. They fall for each other and eventually marry. Her dream of living happily ever after is short-lived when her husband announces that he quit his job and wants to go into business. She supports him throughout the years by working herself to her bone while he coded software in a basement and failed to find investors. When she could no longer take it, she decided she wanted a divorce. She is still juggling jobs years later, to repay the debt she accrued while supporting her husband. She feels life is unfair when she finds out that her husband's business is a success and made him rich. Wanting to even the score, she joins his company as an intern. Thus begins a cat and dog quarrel between ex-husband and wife, who hurt each other, but can’t seem to get over one another. (Source: Mister at MyDramaList)