I read it last month and I'm still thinking about it. The main plot revolves around this novelist, Cecilia, who achieves wild, improbable success with a book she secretly knows she didn't write. A manuscript from an anonymous rival just appears, and she publishes it as her own. The real core, though, isn't the cat-and-mouse with the mysterious writer. It's the internal spiral. She builds this entire glittering life and persona as a literary darling on a foundation of sand, and the anxiety of being exposed eats her alive from the inside, even as she's outwardly celebrated.
It's a surprisingly tense psychological study wrapped in a satire of publishing. You keep waiting for the other shoe to drop, for the rival to reveal themselves and destroy her. But the book is clever because the 'antagonist' is often just her own guilt and paranoia, magnified by the isolating nature of fame. The 'love of my life' from the title becomes deeply ironic—it's this fraudulent success she's married to, and it's a horribly toxic relationship.