"Revenge of the Middle-Aged Woman" a novel by Elizabeth Buchan
Oh, She had it ALL! A good marriage, a great job, grown children and a home filled with......... But Nathan can't compete with the long ago memories of why Rose had married him, so when Nathan tells Rose he wants out of their marriage with, of all people, her younger assistant, Minty, Rose is sure she really can't be hearing him correctly, and when her boss, Timon, informs her that the paper no longer requires her services, she is doubly sure she is hearing Timon incorrectly, but that is indeed the case.
Rose's life, as she has known it, is over or so she thinks. Her grown children, however, force her to put one foot in front of the other, and so Rose starts reinventing her life. Her former beau reappears in her life, but is he and that what she wants? Muddling along, Nathan and Minty start having their own problems, and Rose finds that she doesn't care, and she really doesn't want Nathan back. And then Rose has that "light bulb" moment and realizes that she has become a better person without him.
A Revenge is SWEET!
Elizabeth captured all the emotions one would face in this type of situation. There are two books that follow these folks.
Hope you enjoy.