There are several stories with successfull marriages between huldra and human man. Here is one that are slightly different from other legends I have come across about her. This legend was published in 1948 and collected from north of Norway.
A smart and quick man managed to capture a huldra by throwing steel over her head (common act to capture Huldra). In this way she was bonded to him. She was baptized and became his wife. They lived happily together og got one child.
One evening as the child was sleeping next to the fire, the wife was sitting spinning, suddenly the wife got a strange look, looked at the child and said: ”That one would be a nice steak to roast and eat for dinner”. The man was terrified and the woman understood what she had said and silently said: ”Sorry, please forgive me. ” But the man could not forget. Those words were always on his mind. From being a nice husband, he turned into an angry man. Never saying a good word to her, denying her suggestions, turning his back towards her. This went on for a long while, the wife was suffering in silence.
One day, he working as a blacksmith, she came smiling with food to him. He took the food and threw it on the floor, and continued with harsh words towards her. She then took the hot horse shoe he was working on with her bare hands, twisted the hot iron and said: ”Stop this”. He stopped and the peace was back in their home.