Okay, so you're asking about 'Aphrodite'? There are a few books with that title, so I need to clarify. I'm assuming you mean the novel by Judith Krantz, which was huge in the '80s. The main key character is obviously Lee, the protagonist—she starts as a talent agent's assistant and becomes a huge TV star. Her ambition drives the whole thing.
Then there's Billy, her agent and eventually her husband. He's very much the old-school Hollywood power player, a bit ruthless but you see his affection for Lee. Vito, the TV director, is another major figure; he's the creative force who helps launch Lee's career and has a complicated personal relationship with her.
Lee's friend, the model, and her mother are also important secondary characters that round out her world. The book is a classic Krantz saga—glamour, power, sex, and the inner workings of the television industry. All the characters orbit around Lee's rise, and their conflicts and alliances are what make the plot move. It's a fun, soapy read if you're into that era of storytelling.