it takes two to tango idiom saying
两个人才跳得成探戈；双方都有责任；一个巴掌拍不响
said when you want to emphasize that both people involved in a difficult situation must accept the blame, or that an activity needs two people who are willing to take part for it to happen
She may want to argue, but it takes two to tango and I won't stoop to her level. 她可能想要争吵，可那也得我愿意，我可不想跟她一般见识。