Getting older is something we all experience, but talking honestly about aging, loss, and widowhood isn’t always easy. One author is taking those difficult subjects and finding something unexpected in them: humor. Jacqueline Sideman Guttman is an author and music educator whose latest book, “Widowhood and Other Altered States: Coming of Age at Seventy-Plus,” explores loss, grief, aging, and the many changes that come with getting older.