Without more context, it is difficult to know exactly which king you are referring to. However, it may be the birth of Savitri (the one who married Satyavan) that you are thinking of. In Bharadvaja Sarma's 2008 version of Vyasa's Mahabaratha, Mahabharata 3:277 is cited for the story.
Yudhisthira said, "I do not grieve so much for myself, or my brothers, or the loss of my kingdom, as over Draupadi. In the dicing hall we were brought into the most difficult situation and it was Draupadi who rescued us. She had to suffer again when Jayadhrata abducted her. Has there ever been any woman ever as noble and as devoted to her husband as she is?"
Markandeya said: "You should then hear the history of Princess Savitri, who achieved all the glory that a well-born woman could ever wish for.
"There was once in the land known as Madra a very virtuous king by the name of Asvapati. He was childless and as he was advancing in years he was beset with anxiety. And in order that he could have many sons, he performed all sorts of austerities and he offered one hundred thousand oblations addressed to Savitri, the goddess inhering in the Sun. At the end of the eighteen years, the goddess Savitri came out of the sacrificial fire and offered the king a boon. Asvapati wanted to have many sons.
Savitri said, "I told Brahma about your desire. He said that you would have a spirited daughter. Now I communicate to you at his best what he said. Do not grumble about this anymore."
The king modesrly accepted this boon and the eldest queen in due time gave birth to a lotus-eyed daughter who was named Savitri because she was a gift from Savitri. She grew up to be a very beautiful girl of slender waist and wide hips, like a statue of gold. And her eyes, that were like lotus petals, had such a radiance that prospective suitors were put off by the very splendour of her eyes. Nobody simply had the courage to marry her.
Later in the story, King Asvapati refers to Savitri as "My dear daughter," which implies that he did indeed love and care for her.
It's possible that this is the story that you're thinking of, although it is not from the Devi Mahatmya. I'll keep looking.