How does Alida Spade view her life while her husband is alive, and then afterwards in "Roman Fever" by Edith Wharton?

When Mrs. Slade was younger and her husband Delphin was still alive, every day was exciting; however, after her husband's death, she finds being Slade's widow a "dullish business."

Mrs. Slade's life now is rather dull because she no longer has "exciting and unexpected obligations," such as preparing impromptu entertainment for her husband's business colleagues and going on international trips as his spouse because he was a corporate lawyer. Now, Alida Slade seeks vicarious excitement by following the activities of her daughter as her chaperone, as does her old friend Grace Ansley. While these two women sit on the parapet looking down on the view of a Roman night that promises a full moon, they visualize each other figuratively "look[ing] through the wrong end of her little telescope."

The dramatic irony of this story lies in the misconceptions that the two women have long had about each other since they have viewed one another from the narrow optics of jealousies and resentments. In fact, Mrs. Slade has carried a resentment toward Mrs. Ansley all her life. For, when they were young, her friend Grace was one of those "exquisitely lovely" young women who incite jealousy in even their friends. This jealousy led Alida to fabricate a letter from her fiancé Delphin Slade to Grace, asking her to meet him at the Coliseum under the moonlight. Alida hoped she would wait for him alone and catch the notorious Roman fever. Then, if Grace became ill, Alida would have her out of the way until she was engaged to Delphin and "sure of him." For, she always knew that Grace was in love with Delphin.

In a final irony, Alida Slade finds her moments on the parapet with her old friend Grace Ansley anything but a "dullish business." Rather, they become a victory for the friend that Mrs. Slade has believed all these years to have been defeated. In the same Roman moonlight of years ago, Grace reveals that Delphin did come to the coliseum and, although no one ever knew, he fathered her daughter Barbara.