I'm sorry that your marriage has been difficult so far. I do hope that you and your wife will rekindle the spark that you experienced on your Hawaiian honeymoon. I'm not sure that the black sand had anything to do with your marriage issues, but it sounds as if you are committed to a successful reboot. If you can't mail back the sand, take it to the ocean and release it. The sand will find its way home. Best of luck to you, and I will keep you both in my thoughts.