The Hawaii lawmaker opens up about her life in her new memoir, Heart of Fire: An Immigrant Daughter's Story
Mazie Hirono participates in a reenacted swearing-in with her husband Leighton Kim Oshima
From left: Sen. Mazie Hirono participates in a reenacted swearing-in with her husband, Leighton Kim Oshima
| Credit: Chip Somodevilla/Getty Images

Though they're now living happily ever after, Sen. Mazie Hirono's relationship with husband Leighton Kim Oshima didn't exactly begin as a fairy tale.

Over the past 32 years, Oshima has been at Hirono's side during many career highs — including her 2006 election to the U.S. House of Representatives and her 2012 U.S. Senate race, the body in which she currently serves.

But the couple's union came as a result of more than a decade apart: Time, Hirono says, that allowed them to grow into themselves and deepen their later connection.

"I know that if I hadn't married Leighton, I probably would not have married anybody else because of the way I was," Hirono tells PEOPLE.

The way she was, she describes in her new memoir, Heart of Fire: An Immigrant Daughter's Story, was headstrong and independent with her focus set squarely on fighting injustice through lawmaking, rather than settling down.

In 1974, Hirono was running legislative operations for Hawaii state Sen. Anson Chong when she met her future husband, who had just taken a job in the state attorney general's office and was eager to get involved in local Democratic politics.

Oshima, Hirono writes in Heart of Fire, "was the first attorney I had met who was my own age, and that interested me. But never liking to appear overly impressed by anyone, I gave no outward sign of it."

He paints a different picture of his first meeting with his future wife, with Hirono writing that he saw "a short Japanese girl regarding him with her nose in the air" at a Honolulu Young Democrats meeting.

Over the next year, the two continued to run into one another until, one day, Leighton offered her a ride and asked her to a movie.

Eventually, Hirono found herself "falling for this impulsive, fun-loving man" — one altogether different from herself.

By the summer of 1975, Hirono had been accepted to Georgetown University's Law Center, but she and Oshima decided to maintain their relationship, despite the difference.

The arrangement didn't last long.

"By December, I began hearing from friends back home that Leighton was seeing another woman ... So I dared the uncomfortable thing. I picked up the phone and asked him if the rumor was true," Hirono writes in her memoir.

When he confirmed the rumor, Hirono writes, she ended things immediately: "'Well, then, this relationship is over!' I declared and slammed down the phone."

Hirono wouldn't see Oshima for a number of years and, in the intervening time, found a nickname following her around coined by male colleagues: "The Ice Queen."

"I view that as very much a projection of how I was at the time," Hirono tells PEOPLE. "I first ran for office in 1980. Every time [my male colleagues] sort of hit on me I would just act like, 'What?' I just never paid the many attention."

Hirono says that, rather than see the nickname as derogatory, she felt it showed that the male lawmakers with whom she worked "respected me for the substance of the work I did."

Senator Mazie Hirono
Senator Mazie Hirono
| Credit: Nicola Gell/Getty Images

By 1987, Hirono — then a state legislator — was ready to settle down, having recently turned 40. That didn't mean she was going to transform herself for someone else, though.

"I had recently decided I was at the point in my life where I could handle being a legislator and being a wife," she writes. "I was very clear, however, that the person I chose to marry would have to be at peace with me never assuming a traditional wifely role."

And so when her path crossed with Oshima's again, she wasn't all that eager to settle down with him — but their connection re-sparked at a celebration to kick off the opening of the new legislative session.

According to Hirono's memoir, Oshima said that he had recently seen her standing alone on a street corner one morning, sign-holding while he was driving in his gold Mercedes.

"'I didn't toot my horn and wave as I drove by because I didn't think it would be appreciated,' " he told her, she writes.

"'You're right,' I agreed. 'I would have given you the finger.' "

As the two shared a laugh, Hirono writes, she "realized that enough time had passed since our breakup that I no longer harbored open animosity toward Leighton."

But that didn't mean they were falling right in love. In their time apart, both had grown in their careers — and settled into long-term relationships with other people.

Mazie Hirono
Mazie Hirono
| Credit: Carolyn Kaster-Pool/Getty Images

After Oshima got a divorce from his first wife — and after Hirono ended her relationship — he came calling again.

Just two years later, he and Hirono were married, selecting the auspicious date of Aug. 8, 1989, "hoping the lucky repetition of 8s would not only bestow good fortune but would also help us remember our anniversary," Hirono writes.

Looking back, Hirono is grateful for the time she and her husband were not together, growing into themselves before they reconnected.

"I am very self-contained. For a lot of my adult life, I lived by myself until I got married," she says.

But in Oshima, she found a partner and a champion, someone who allowed her to forge her own path. Five years after their small backyard wedding at the governor's house, Hirono decided to launch a campaign for lieutenant governor of Hawaii.

When a reporter asked Oshima if he would serve as Hirono's "chief political confidant and adviser," he answered that "Mazie has much smarter people whom she hires to be that."

""But," he added, "I say the last things to her at night and the first things to her in the morning."

The path that brought them together was winding. Hirono, now 73, would not add a single shortcut.

"I often tell Leighton if we had gotten married when we were together in our 20s, I think we might have gotten divorced," she says. "We both came together 13 years after we broke up ... and here we are, over 30 years married, very happy with each other."

Heart of Fire: An Immigrant Daughter's Story is out now.