My Contract Wife's Billionaire Lover

Zoe is married to a man who loves her half-sister, and she does not mind. The marriage is a contract with a fixed term, and when it runs out she will be free. She agreed to it out of gratitude. Her family had fallen, an old man helped her out of trouble, and she married his grandson to repay him. She had never believed in marriage anyway, after what she saw at home. Then she runs into a rich heir she knew before the wedding. They met by chance two years ago, when neither of them was married, and there were several affairs between them that caused a scandal. Now she has a husband and he is still single, and he goes after her openly, even though that makes him the other man in everyone's eyes. Zoe holds out for a while, then starts to waver, and step by step she lets him closer.