Leah Dieterich’s memoir, “Vanishing Twins: A Marriage,” tells her story in bits and pieces.

Sometimes the diary-like pages comment on the outside forces around her, like her parents, teachers, and later, her lovers. Other times, her words are the ones in her head as she figures out her sexuality and the boundaries of her various relationships.

As evidenced by the book’s title, Dieterich uses the concept of twins as a recurring motif in her book. At times, she uses it to compare her feelings of sameness with her lovers or as a comparison to twins in history, literature or dance.

“I came upon a statistic about vanishing twin syndrome – that one where all pregnancies begin as twins and one twin isn’t viable and doesn’t survive. I felt this real flash. Oh my God, maybe that’s why I’m so interested in this. Maybe that happened to me. Maybe I’m the surviving member of a vanishing twin pair. That’s when that theme really began to kind of guide the book,” she says.

Dieterich says she had to make a series of decisions regarding what to put in or leave out of her book.

“It’s all about memory. Things that felt more vivid to me were the things that I decided to keep,” she says.

Certain themes or ideas that didn’t fit into the narrative of her exploration of her relations were left out. “I just relied very much on the natural kind of way things were rising to the top,” she says.

Looking back wasn’t always out of rosy nostalgia. There are a few times in “Vanishing Twins” where Dieterich hints at feeling embarrassed by her former younger self.

“I saved a lot of instant message transcripts, and I read through every single one of those,” she says. “It took me months to read through some of this stuff and reading my own part of the dialogue ... It’s instructive and also kind of nice to have that distance and see, ‘Oh yeah, I’ve come a long way to be able to see myself from the outside a little more.’”

One of the aspects of Dieterich’s book that stands out is her frank openness and examination of her changing sexuality. She recalls moments when she was interested in women, then men, then women again. Eventually, she wants to identify beyond bisexual, and toward the end of the memoir, she declares her identity as queer.

“I think over time it’s gotten to be more acceptable in society to talk about different kinds of relationship arrangements, gender and sexuality,” she says.

“I sort of feel like everyone will eventually call themselves queer and then what will it be?” Dieterich adds. “I just really wanted very much to have a word, but a word that wasn’t so black and white or wasn’t so easy to pin down.”

Although Dieterich’s open marriage is a constant throughout most of the book, she says she and her husband are back in a monogamous relationship. “I think it was easy for me to talk about it once I was no longer in an open relationship,” she adds. “Once I was back in a monogamous relationship, I think I felt the stability I needed to talk about it. When it was open and the ground was so shifty, I don’t think I had enough to stand on to tell the story in a coherent way.”

Near the end of Dieterich’s book, she reflects on other artistic couples with open marriages, like Frida Kahlo and Diego Rivera. Their connection to the arts and each other fascinated her, as she and her husband also share creative interests.

“I felt like all of these really interesting creative couples had these kinds of open relationships,” she says. “I began to wonder if it was necessary in some way to continue to both realize our creative potential while staying in a relationship with each other. ... Their stories are so crazy, but theirs are also stories we remember.”

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