I like to write and read sex-positive stories, certainly. I have a story for another time about how sex-positive erotica is actually what made me understand feminism and become willing to call myself a feminist.
However, not all of my writing and reading is sex-positive, and there are a lot of complicated reasons for that. Roberta gives a nice account of why sex writing needs a range that includes the very unpleasant:
If sex is all metaphors, it can't always be a simple way to get happy. Sex can be a desperate, doomed attempt to bridge a gap in credibility or understanding. It can be an extreme form of exploitation. It can be the event that turns a high school girl who is desperate to fit in into a target for contempt from everyone she knows. It can be an attempt to prove something improvable. Sex can be an act of self-hatred, or hatred of the other. It can be the means by which invading armies literally colonize the bodies of civilians, hoping to impregnate as many "enemy women" as possible. Sex, broadly defined, can destroy both body and soul.
Should erotic writers avoid saying anything disturbing about sex? The terms "adult" and "mature" are often used as euphemisms for sexual content, yet to avoid mentioning any negative emotions (guilt, hatred, rage, fear, despair, regret, etc.) in connection with sex is to limit oneself to a fairly childish view of the world.
I started writing erotica because it's the genre where I feel most honest as a writer. It's the subject on which I really have something to say. And I'd definitely be lying if I pretended all my experience with sex has been pleasant or positive. Sometimes, I feel strange about the range of my work. I worry that some of my dark work for Forbidden Fiction, for example, would freak out readers who enjoyed, say, my light piece in the Cleis erotic romance anthology, Passion. I also worry that readers who like the dark stuff will find my happy endings fluffy. But I need that full range to say all of what I have to say about sex, and I try not to censor myself in either direction.