What a beautiful quilt!!! It's a shame that you haven't felt comfortable enough to use it. After 17.5 yrs of marriage it's probably a safe bet to go ahead and use it now. Maybe now that you also quilt you can understand why she would want it to stay in her family.
People say the dumbest things at weddings. At my first one when I told one of my new husband's sisters that I was glad to finally meet her she looked at me and said, "That's fine but I want to tell you right now that _______ (his first wife) and I were BEST of friends." (They'd gotten a divorce 3 yrs before I even met him) But I even surprized myself when I smiled and replied, "I think that's wonderful. I've met her and she seems like a very nice person."