“They couldn’t put her in a phone booth – that’s what Superman did,“Cartertells PEOPLE in this week’s issue. “They wanted to put me on a lazy Susan and I thought that was ridiculous, so I said, ‘Why not a dancer’s pirouette?’ And that was it. That’s how Wonder Woman’s transformational spin was created.”

Now, nearly five decades later, the actress who first brought the Amazon princess to life, wearing star-spangled armor and bulletproof bracelets, is having to figure out her transformation once again. This time after the loss of her husband of 37 years, Robert Altman, whodiedin February of myelofibrosis, a rare blood cancer.

“The next part of my life is I want to learn who I am,” says the 70-year-old star. “It’s totally frightening. I don’t know who I am without Robert.”

“It still gets me,” she adds, dabbing her eyes between a few tears. “I just can’t believe I’ve lost him.”

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lynda carter and robert altman

In the months since his death, she’s returned to her first love — music — to cope, as well as to honor his memory. On Friday, she’s releasing a new song,Human and Divine, which she wrote in tribute of their nearly four-decade love affair. “It was a real romance,” she says. “I was really trying to define love and loss and and make sure it was about the human-ness of love.”

LINDSAY ADLER

lynda carter

They had two kids: James Altman, 33, an attorney, and Jessica Carter Altman, an attorney turned singer-songwriter. And like any good love story, there were challenges. “We’d been through ups and downs and ins and outs,” says Carter, “and I’d never in my life felt the love and the support and the thrill of having a guy like this.”

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lynda carter and robert altman

For more from Lynda Carter, pick up the latest issue of PEOPLE, on newsstands Friday, or subscribehere.

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wonder woman

And like all good superheroes, Carter is apparently ageless. Along with her music, she has a new indie movieThe Cleaner(in which she plays “a kooky older woman”) co-starring Shelley Long andLuke Wilson. As for turning 70, she says with a laugh, “It’s such a big freakin' number. But it’s kinda fun. I feel like the Rolling Stones. They’re in their 70s and they’re rolling towards their 80s!”

Besides, isn’t age a relative concept?

source: people.com