The emperor pushed Ruyi down for his concubine! I regretted it when I found out she was pregnant! 

Her treachery was motivated by her pathological desire for two things: her son to become Crown Prince and all that would entail for herself and her maiden clan and her maiden clan love of her life (one sided, btw), to desire her, favor her even though they couldn't be together because she belonged wholly to the Emperor and no man would ever touch her other than the Emperor; prior to becoming a member of the harem, she wanted to marry her clan's Crown Prince believing most of her life they were compatible in all ways. In the end, her legitimate royal-blooded sons were removed from her palace as her punishment and banishment from palace life, they were married to women far away so not close by to even visit her or send her messages, and were too ashamed of her behavior and her permanent demotion/punishment by the Emperor to even visit when back in the Forbidden City and main palace grounds. In her final days, even her nobility was yanked from her grasp when the clan Crown Prince admitted to the Emperor she was nothing more than a commoner; an orphan, raised to believe she was much more in the hopes of her becoming a member of the harem some day and she meant nothing to him other than a loyal servant helping maintain the clan, its wealth and prominence in the empire by having her serve the Emperor in bed and produce heirs. She was a tough woman who did everything for a mere smile from her 'prince' whom she truly loved from girlhood and rarely saw unless the CP visited the palace, but his denial of her nobility in their clan and his disregarding her as nothing more than a common servant for the good of the clan broke her. She withstood a lifetime in the harem of jealousy, treachery, murder, attempted murder, intrigue, malicious intentions, betrayals, lies, deceit, torture, and gave as good as she got, if not more to the other harem women, but her unrequited love of her own Crown Prince and his admission of same by denouncing her and abandoning her in her very vulnerable moments was her undoing. In the end, she and the woman she hated more than any other in the harem (Ruyi) both died on their own terms, both having zero respect for the Emperor, despising him in his weakness, cowardice, pathological inferiority complex and who was too easily manipulated by superstition, jealousy and his own ego; both women, knowing they were nearing death, prayed for the identical things: freedom and peace.