The union of Luther and Catherine, though without the raptures of a first affection, was no doubt a happy one. The Lord greatly blessed them. She seems to have been a woman of great modesty, with tender affections, and more than an ordinary share of good sense. She consoled him in his dejection by repeating passages from the Bible, saved him all anxiety about household affairs, contrived to sit near him during his leisure moments, amused him by working his portrait in embroidery, reminded him of letters he had to write; but sometimes she indulged rather more in general conversation than suited the doctor, which called forth his most playful sallies; such as "Did you say your Pater, Catherine, before you began that sermon? If you had, I think you would not have been allowed to preach." And sometimes he addressed her as my Lord Ketha, and the Doctoress. But his letters overflowed with tenderness for Catherine; and as age advanced, his affection seems to have increased. He styles her his dear and gracious wife, his dear and amiable Ketha.
They had six children, three sons and three daughters. Their daughter Magdaline died at the age of fourteen. "Such is the power of natural affection," says the father, "that I cannot endure this without tears and groans, or rather an utter deadness of heart. At the bottom of my soul are engraven her looks, her words, her gestures, as I gazed at her in her lifetime and on her death-bed. My dutiful, my gentle daughter! Even the death of Christ-and what are all deaths compared to His?-cannot tear me from this thought as it should. She was playful, lovely, and full of love."
The Elector provided for the mother and the five children after the father's death.