DEAR MISS MANNERS: Fifteen years ago, I received a ring as a birthday gift from my boyfriend at the time. He insisted on giving me a diamond cocktail ring, but I was firm on its being a gift only — not a promise or any kind of engagement. (I didn’t want to be in such a relationship since I had just left an abusive marriage.) We broke up two years after that, and had absolutely no contact from then on. Move forward to today, and I have found out that he passed away. The ring doesn’t mean much to me aside from being beautiful, and I don’t wear it anymore. I’m wondering about giving it to his da…