Heather Milligan and Arnold Schwarzenegger in Zurich on Sept. 30, 2015.Photo:Andreas Rentz/Getty

Actor Arnold Schwarzenegger and Heather Milligan attend the ‘Maggie’ Premiere and Golden Icon Award Ceremony during the Zurich Film Festival on September 30, 2015 in Zurich, Switzerland.

Andreas Rentz/Getty

Arnold Schwarzeneggeris opening up about his decade-long relationship with girlfriendHeather Milligan.

During a wide-ranging chat in this week’s issue of PEOPLE surrounding the upcoming release of his motivational bookBe Useful: Seven Tools for Life, the 76-year-old actor says his relationship with Milligan, a Los Angeles-based physical therapist, “is fantastic.”

“We have so many things in common,” theTerminatorstar says. “I think the world of her. I love that she’s into working. She’s clearly independent. She just is driven as hell.”

Schwarzenegger credits Milligan, 48, for putting herself through college and a master’s degree in business with student loans and jobs like bartending, noting that she “grew up tough.” He also said admires how she is the “driving force” in her family, having cared for both of her late parents as they battled cancer two years apart.

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Book cover for “Be Useful: Seven Tools for Life” by Arnold Schwarzenegger

Schwarzenegger adds that Milligan recently returned from Nebraska, where she was helping care for her grandmother. “Every night, she’s with her grandmother on the phone for at least a half an hour,” he says. “I mean, that’s when you get to know a person, the heart they have.”

Milligan and Schwarzenegger met in 2012 following his shoulder surgery as he was preparing to film 2013’sEscape PlanwithSylvester Stallone(who, coincidentally, had shoulder surgery the same day).

Wanting to get in fighting shape in just three months before cameras rolled, the star asked his surgeon for a recommendation.  “I said, ‘I got to go do this movie, and I bring a lot of punches and I have fights with Sly and I want to have my act together.'”

“And so he says, ‘There’s only one (person), it’s Heather — any athlete, I always send them to her, because she’s the only one that really knows what they’re talking about.’ So I went to her, and then after my therapy was finished, after I was finished with the movie, I called her back and took her out for lunch to say thank you. And then one thing led to the next.”

Maria Shriver and Arnold Schwarzenegger with their children.Katherine Schwarzenegger/ Instagram

Katherine Schwarzenegger Instagram, Maria Shriver, Arnold Schwarzenegger

Katherine Schwarzenegger/ Instagram

Milligan has expanded her business over the past decade and today runs Elite OrthoSport, one of the largest physical therapy clinics on the West Side of Los Angeles, says Schwarzenegger, who enjoys dropping in to chat up clients that span NFL players, NBA stars and UFC champions.

“I schmooze with them while they’re getting therapy, because I admire them, they’re great athletes,” he says, adding with a grin, “Even though a lot of them make me feel like a little chicken.”

Schwarzenegger also opened up about his friendly relationship with ex-wifeMaria Shriver. The former couple’sdivorce was finalizedin 2021, after Shriver, 67,filed a decade prior.

The pair continue to regularly make joint plans with their childrenKatherine, 33,Christina, 32,Patrick, 30, andChristopher, 26, including a recent celebration for Patrick’s 30th birthday.

Schwarzenegger says he and Shriver, who are now grandparents to daughter Katherine’s children —Lyla, 3, andEloise, 16 months, with her husbandChris Pratt— prioritize such family moments, despite having separate lives now.

“We always communicate about the kids, about the holidays, about birthday parties and Mother’s Day parties and Christmas,” he tells PEOPLE. “Even though it’s a different relationship, there’s no reason for me to feel anything other than love for her.”

Be Useful: Seven Tools for Lifeis out Oct. 10, and available for preorder now onamazon.com.

For more from Arnold Schwarzenegger, pick up this week’s issue ofPEOPLE, on newsstands Friday.

source: people.com