The Dying Animal by Philip Roth
About an old professor with minor celebrity status that he uses to lay a boatload of young women
He then finds one that is ridiculously beautiful and then falls for her. Her youth and beauty sorta act as a first time reflection of his own fading life, and he begins to become extremely jealous, possessive, angry, as their "fling" comes to an end and he tries to cope.
It's a truly remarkable book. A tad on the raunchy side, and with countless passages dedicated to breasts.
But the book is only like 120 pages, so well worth the read.