So my fiance and I got engaged without a ring, mostly because it didn't really matter to me if I had "the ring" or not and also because it was a spontaneous proposal. But last night, FI planned this big romantic night and at the end of it gave me a beautiful ring. Come to find out, its actually his moms old engagement ring. She never wore it after getting married because it clashed with her rather large wedding band. So she gave it to FI to give to me. He got it cleaned and resized blah blah blah. My point is, is there a proper way to thank his parents for giving us the ring? It was extremely generous and I felt very overwhelmed with emotion when I found out the origin of the ring. It means so much to me and I'm just not sure if there is a right or wrong way to thank them for something like this.