What Jane Seymour Learned from Her 'Painful' Divorces: 'The Sooner You Can Accept It, the Better'

Jane Seymour has learned a lot about love and loss in her lifetime, but the biggest lesson she has taken from her past relationships is perspective.

The 69-year-old actress, who has been married four times total, tells PEOPLE in this week's issue that what she has learned from going through divorce "is to let go. To try to find a way to communicate and keep what was good in the relationship."

"Especially when co-parenting," Seymour, whose new comedy The War with Grandpa is now available on DVD, Blu-ray and on-demand, adds. "And I tried to look at my side of things: 'What could I have done differently?' But it's hard when you're a mother and you work. It means sometimes you're gone. And sometimes you may be in a relationship where they would rather that you were there 24/7 and never worked."

"That hasn't actually been the case with me, but that's the only thing I can look at that I did really wrong — I went to work," she says, laughing. "But I was providing for the whole family, so it's very hard."

Seymour shares twins Kristopher and John, 25, with actor ex James Keach. Keach, 73, and Seymour were married from 1993 until they separated in 2013; their divorce was finalized in 2015. Before Keach, Seymour was married to David Flynn, with whom she welcomed son Sean, now 35, and daughter Katherine, now 39. Seymour is also close with her ex-husbands' children from previous relationships, Jenni Flynn and Kaelen Keach.

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"I've always done the best I could; I took my kids all over the world whenever I was working, I had them on-set with me. And I somehow managed to juggle it. I was married to men who had different issues, and I never ended the marriages — they did, by finding other people!" she continues with a laugh.

Seymour was also married to Michael Attenborough, the son of Richard Attenborough, from 1971 to 1973, before marrying Geoffrey Planer in 1977 (they divorced the following year).

Asked how she dealt with the issue of divorce and came through the other side stronger, Seymour calls the process "painful," "depressing" and "anger-making," and says it took some perspective that she learned from her mother — namely, in knowing "that everyone in life faces challenges."

"The sooner you can accept it, the better for you and others," she says. "And then when you look out from yourself and look around to see what other people are suffering or challenged by, you realize what you have is minimal compared to other people's challenges."

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"And so for me, I was really brought up to see what I could do for others, because that would give me a sense of purpose. When I had a sense of purpose, I was able then to deal with what I had to deal with," adds the former Dr. Quinn, Medicine Woman star.

Of making The War with Grandpa alongside some other big names in Hollywood like Robert De Niro, Christopher Walken and Cheech Marin, Seymour says the experience on the film — which focuses on a prank war between a grandfather (De Niro, 77) and his grandson — "brought the child out in" her "dream" team of castmates.

And reuniting with Walken, 77, was a joy, as he "hasn't changed a bit" since they played a married couple in 2005's Wedding Crashers. "I loved working with him then and I loved this time too," she says. "Chris Walken is who he is ... what you see is what you get. What you see on film is how he is in real life. He's hilarious."

The War with Grandpa is available now on Blu-ray, DVD and on demand.

For more from Jane Seymour, pick up the latest issue of PEOPLE, on newsstands Friday.