This is true. I loved my MIL to pieces. She was wonderful in almost every way and one of the smartest persons I've every known. And a great friend, too. My wife used to kid us and say that when we were together, we appeared more like a married couple than in-laws.
She died a couple of years ago, and I was inconsolable for weeks afterward. I'll never truly get over her passing and carry her memory in my heart every moment of every day.