That's again DKDM version. The DP & the scripts of 10 Mahavidyas doesn't say that. So for me Sati was Goddess ParaShakti's avatar, was born as the result of Daksh's penanace, she is taking this birth to unite with Shivji, will be born as his daughter but when he'll insult her husband, she'll leave him & go.
DP mentions Shivji did penanace to get Goddess ParaShakti as his wife. She appeared in a ferrocious form infront of him, but he was not scared. She then told him, she will take birth to unite with him. So if Shivji did penanace to get her, why will he not accept her?
I believe those scriptures more as they have further reference in some other scriptures.
DKDM plays a lot with the Purana's stories, which are not accepted to those who have read, known those stories.
Anyway everyone can have their own views.