05/25/2012 04:11 pm ET Updated Jul 25, 2012

Warning: Explicit Sexual Content

Before we begin, if you're under 18, or one of my children (even if you're over 18), or one of my children's friends, or someone who works for me, or my Mom or Dad, you should stop reading and close your browser now.

I'm serious.

OK, now that it's just this writer and the anonymous, adult public, I'd like to talk about sex -- specifically the sex in literature, and even more specifically the sex in The Forever Marriage. Because there's, well, a ton of it. It's graphic, and according to all good sources it's really hot.

I did not set out to write the book this way. Granted, I was in Italy -- on the Cinque Terre -- when I came up with the idea and the characters and committed the first words to paper (or screen, as it were). And I was still pretty newly married at the time, dazzled to find the same great one-night stand in my bed night after night.

I was also in my early 40s, and I think this is key. Because if my friends and I are representative, this decade is the most sexual time in a woman's life. Mature enough to know what she wants. Done with the crowd-driven insecurities of youth. Inhabiting a body that's desperate to produce one more time, no matter how many ways it's thwarted. Coupling, if she's lucky, with a middle-aged guy whose table stakes are intellect, gentility and humor. (Nothing is sexier than that.)

I write chronologically. So I began the story, as I've detailed, with a woman watching and reveling in her longtime husband's death. I introduced her lover, a younger half-Irish, half-Indian librarian (vitality, exoticism and brains) in the second paragraph and had her texting him inappropriate messages by page four. This was an emotionally true but raw story that displayed the terrible suffering -- both physical and emotional -- of a man named Jobe. As I moved through it, quickly falling in love with the cuckolded husband myself, I felt the need for balance. I genuinely wanted to give Jobe something joyful and sweet.

I gave him sex with the wife he both feared and adored, on page nine:

They hardly kissed any more; she couldn't remember the last time she'd encountered his tongue. But that night she'd tried, a drunken experiment, and his beard felt stiff and foreign against her cheeks. Within minutes, Jobe was inside her and his long, bony body was against hers, like a pencil indenting a soft eraser. He moved in and out, pistons working. She couldn't have reached his mouth again if she had wanted to -- he was rigid and had drawn back for thrusting, so his face was too far above her head -- but this only added to the alchemy. Alone beneath Jobe, Carmen entered a dreamy place where divisions disappeared.

I admit, this is a reserved, not-quite-coy description of the act. But it was more sex than I'd ever written in my life. My first novel featured a young, married couple very much in love, but the few sex scenes were only glancing allusions, described in vague language and taking up only a few lines. Here, I was writing about a marriage doomed to end with a husband's welcome death. Yet the scene genuinely taught me something about my characters: Jobe, workmanlike and hopeful and anxious to please; Carmen, self-absorbed but not heartless, a woman who despite her distaste recognized when her ill husband needed the comfort and earthly gift of entering her, his mortal body cradled in her wetness and warm skin.

I wrote on. I became more comfortable with the words and body parts and depictions of slippery, heated moments usually kept private. And I realized that the carnal behavior of my characters very clearly defines them: Jobe, Carmen and Danny, her librarian. Even Jana, a lesbian with a strict code for sexual morality, who becomes Carmen's confidante, caretaker and guide.

Carmen's first interaction with Danny happens toward the end of Chapter 1. It's a phone call during a thunderstorm, which she must conduct quietly because her teenage children are in the next room. And it establishes the dynamics of their relationship in fewer than 150 words.

"I'd ask if you want to meet me, but I don't know where we'd go in this storm. " He seemed suddenly to crouch closer to the phone. "It would be nice to touch you. I'd lick you and make you come, then leave right away. Run away through the rain."

Carmen slid one hand up along her thigh. Danny electrified her with his dirty talk, and his habit of sometimes doing exactly as he said: working her up quickly, bringing her to climax, and disappearing before she'd even had time to open her eyes. The first time they were together she'd felt as if he were an incubus or a spirit, something she'd conjured up for the purposes of satisfying her the way her husband did not and allowed to dematerialize as soon as she'd gotten what she wanted. But that only made her want him more.

The plot often turns on how sexuality shapes events, but it is Carmen -- the novel's most constant presence and point of view -- whose desires keep coming to the fore. The Forever Marriage is written in "close-third," which means it does not have a narrator (an "I") but it takes place both inside and out of Carmen's head, always in her immediate sphere.

That means readers are let in on her most private thoughts: how she yearns for Jobe's death and occasionally resents her children. But also, what she thinks about as she masturbates in the attic, while listening to one of Jobe's favorite classical CDs.

The music changed, becoming a soaring symphonic rush -- an early ancestor of the Moody Blues -- for which she was grateful. Carmen was breathing raggedly now, pressing down harder and arching her back to rub her nipples against the coarse blanket, which she held taut with one hand. Her eyes were closed but dots of gold light appeared behind them, larger and larger in succession. Her shoulders were opening like wings, her whole body thrashing and about to break into waves, when she felt suddenly that she was being watched.

This may be one reason The Forever Marriage was rejected by the first three rounds of publishers. It's an odd animal: women's literary fiction -- NOT erotica -- with a brazen, sensual and deeply flawed main character. Carmen is perpetually concerned with, touching and baring her body. Yet the sex never becomes the story; it isn't that sort of book.

My goal was to write an honest novel that looked unstintingly at deep, complicated, visceral things: marriage, cancer, regret, sex... even math. To me, they are all connected, these wonderful, painful bounds of space and time and one's brief, limited existence. That's what I wanted to show.

And to some degree at least, I think I succeeded. Early reviewers have referred admiringly to Carmen as a "hot-blooded woman" and cited "the potency of Carmen's desires" as driving the way The Forever Marriage unfolds. This is sex as that cry against the darkness, the unknown, and the infinite universe.

Sex as we practice it in life.