Counterattack System appeared when I'm already At The Mahayana Realm - Chapter 179 - 178: Black Market Medicine

With a marriage contract forcefully done, he married her, and all she could do was comply, and resent him deeply for that and for all the following misunderstandings they faced.
However, it was already too late when she understood she actually loved him.

Knowing she married a wrong guy, what would she do to deal with the subsequent marriage lives?

In order to pay for her brother’s medical expenses, she had to replace her own sister to marry the rich family's elder son . She always thought she was married to the elder one, but she did not know her husband was nominally the younger son He Yi Ning.

He Yi Ning, the real heir of the rich family, the ruthless business emperor, the ruthless workplace tyrant, and her sister’s dreaming husband. When she found out that the person who married her was He Yi Ning, she stunned and asked, “Shouldn’t i be your sister-in-law?” He smiled charmingly: “Are you unhappy with your husband?”

He was the youngest guru of martial arts as well as the perfect Mr. McDreamy of the most girls. He had mysterious absolute touch, clear-sighted observation ability and various outstanding talents.

She was drugged by her ex-boyfriend and had her first night with a mysterious man.