Selma Blair Remembers Being Sexually Assaulted by a High School Administrator: 'He Broke Me'

Selma Blairis a survivor of sexual assault.

In her new memoir Mean Baby, the actress is sharing for the first time the pain and shame she endured after a trusted authority figure assaulted her as a teenager.

"I counted on him for everything," Blair says of her relationship with one of the deans of Cranbrook boarding school she attended in Bloomfield Hills, Mich. "I really couldn't believe my good fortune in having such a wonderful mentor and friend. What hurt me from this was that he would make such a mistake. That was it."

In an exclusive excerpt from Mean Baby in this week's PEOPLE, Blair details the disturbing moment when the dean crossed an unforgivable line.

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"I thought he was the greatest man I had ever met," she writes. "Handsome. Tall. So generous. I'm sure you can see where this is all going. But at that time, I couldn't have predicted it. I trusted authority. I was just a teenager."

It was the day before winter break her freshman year, when Blair went to the dean's office to say goodbye and where they exchanged gifts.

"We embraced. It felt too long and too still and too quiet," she writes. "His hand went to the small of my back, tracing the space just above my tailbone. His lips were on my mouth. Please, I thought. Please don't go under my pants, my dress-code-approved Ralph Lauren khakis into which I'd carefully tucked a plaid shirt Please. You are a grown-up and I love you; please do not put your hand inside my pants. But he did. It was a simple thing. He didn't rape me. He didn't threaten me. But he broke me. Nothing ever happened again, but I never felt safe."

She continues: "When I told my mother he had kissed me she took a deep breath. "You must not tell anybody. He's beloved at that school. And you'll just be a troubled girl . . . I'm sorry." At the end of my senior year, he came over to congratulate me for winning a writing award. Then he turned to my mother and said, "You must be so proud." She just looked at him, stone-faced. Then: "I know what you did. Stay away from my daughter." He walked away."

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"I didn't have the energy or experience or the shame factor or the confidence to deal with any of this. And it affected me so very much. I worked very hard in the book to try and [explain] what it was. It was too disarming for me. I was careful, I never wanted him to be in trouble either."

For much more on Selma Blair and Mean Baby, pick up the latest issue of PEOPLE on newsstands Friday

Looking back on and writing about some of those exceptionally painfully memories has given Blair a deeper understanding of her own internalized trauma and that she will always be trying to heal from it. And although she says she does not let her previous negative experiences with certain men impact how she views her romantic future, it is not a priority for her at the moment because she is happily busy being a single mom to son Arthur, 10 (dad is ex Jason Bleick, a fashion designer).

"I've had some wonderful relationships where there wasn't drama," she says. "But I don't even think of [future romantic relationships]. I know with everything that life can bring, that I really don't say 'never' to some things-- I say never to alcohol -- and there are a couple things for which the dance card is full unequivocally, but I wouldn't say never [to a relationship]. It's just not at all where my energy lies. Everything is with Arthur now."

She adds: "I feel much more secure in my life," she says. "As long as my son is okay, and I don't have an immediate death sentence or am in immediate peril, then I could probably handle anything."

Mean Baby is available May 17.

If you or someone you know has been sexually assaulted, please contact the National Sexual Assault Hotline at 1-800-656-HOPE (4673) or go to rainn.org.