I feel sorry for the poor chap, but I don’t think he’s missing out on the relationship if she refuses to talk to him unless he gives her an expensive piece of jewelry. I understand that she would be upset by such a horrible loss of money (believe me, I really grok that), but accidents happen. Move on. Don’t refuse to talk to him. Start a fund raiser. Start a hunting party for the ring. Wear a plastic lollypop ring until a replacement is had. Ceasing to talk to him is exactly the incorrect response.