In Pan Jinlian's mind, the person she married should be like Wu Song. But the reality was that her husband was an ugly, short man who couldn't be flirtatious. Therefore, Wu Dalang failed to satisfy his wife both materially and spiritually. If Pan Jinlian had been an ugly woman herself, she might have resigned herself to her fate, but God had given her good looks, and she was naturally unhappy. After failing to hook up with Wu Song, and after she was humiliated by him, her mindset began to undergo a 380-degree transformation. That's when Ximen Qing set his sights on her, and she just happened to be lonely, so she started to get good with Ximen Qing.
Ximen Qing looks very good, but also has the power, even to him as a concubine, I guess Pan Jinlian is also willing to do it. But the original Pan Jinlian is not like this, she is very backbone, if not refused to give the big family as a concubine, will not be reduced to give Wu Dalang as a wife. So in this process, in fact, Wu Song's behavior still has a great influence on her. Just like in real life, if we are y hurt by the one we love, we may change a lot in our life afterward. Will lose faith in the world, will slowly fall.
Pan Jinlian is nothing but a tragic figure under the feudal society, she is a woman who makes people sympathize with her and a woman who makes people hate her. Many people feel that she is an adulteress, a woman who does not abide by the ways of women, if you are in her position above, you may not be able to do better than her.