The marriage appears to have been a happy one. Meresankh became second wife, although continuing to assert her claims by her title "king's daughter" and "beholder of the horus and seth". As her father died before ascending the throne she was never a king's daughter, but a king's granddaughter. By Rekhaef she had more than six children. Some of their names were:
Nebemakhet (m), Shepsetkau (f), Dwa're (m), Niuserre (m), and Khenterka (m), besides several unnamed daughters.

She was also not content to remain in the background. Both her and her mother became prominent at court, on sculptures and inscriptions. Her eldest son would eventually become superior lector priest and vizier. While there is no proof for this hypothesis, her eldest daughter may have (if tradiition was followed) married Menkaure, as she would've been the next heiress.
Her son eventually married and had children of his own. Technically, he was heir to the throne - as was his children. They would never again be in line for the throne. They had grandma to thank for that!