After the Side Character Transmigrated into a Book and Dumped the Male Lead

Su Yu'an transmigrated into a book, becoming the female supporting character in a sweet romance. Only, in the original story, she was neither the one loved nor the one doted on. Su Yu'an decided she didn't have to hold on to this marriage. If he wanted a divorce, fine! She'd cling to her little brother and live carefree from then on! One day, a man saw a photo shared on his ex-wife's brother's social media feed, and his face instantly darkened. Who were all those men around Su Yu'an?!