"It was these mutual attitudes which enabled both of us to live in the fourteen years of our married life in the greatest happiness possible for human beings on earth."
She took over his business affairs and got him out of debt.He was addicted to gambling and in the first years of their marriage he actually lost all of his money including all of her clothes.
From what I've read their mutual interest was that they eventually both became mutually interested in her taking care of things and him writing books. The article also indicated that she was actually quite enamored of him and even though she was only 35 when he died she never remarried.
Sounds like true love and an ideal match to me.