The 44-year-old "Mad Men" star announced the news on Instagram Thursday, writing, "Twelve years ago we fell in love and became partners. We joined our two amazing families, had countless laughs, made wonderful friends and were blessed with incredible opportunities."
"Today we take our next step together, but on separate paths," she continued. "We will always be grateful for the love we've shared and will always work together to raise our two beautiful dogs."
Henricks went on to say that she and Arend, 41, "will be taking time to rediscover" themselves as they transition into this next chapter. She also thanked everyone for their "patience and support" and asked for "space" at this time.
Waiting for your permission to load the Instagram Media.
The "Toy Story 4" star and "Madam Secretary" actor tied the knot in October 2009 in New York. They celebrated their 10th wedding anniversary earlier this month, which Arend commemorated with a cryptic Instagram post.
"Anytime you're feeling low, bookend yourself in dogs," he captioned photos of himself with the couple's pets. "Can't recommend it enough."
Hendricks, who is currently filming the third season of NBC's "Good Girls," told Health magazine in 2014 that she and her husband "decided that we are not really interested in having children. It seems like it's expected that you'd want to have kids."
"It's just very normal for people to say, 'Well, when you guys have kids...' And then when I say, 'Actually I don't think we're going to do that,' people will say, 'Oh, you say that now...'" she said at the time. "It doesn't bother me, though. And, you know, there's a small chance I could change my mind."
Hendricks met Arend in 2007 after being introduced by her "Mad Men" co-star, Vincent Kartheiser.
"Geoffrey walked in and I was like, 'Who is this guy?' He had amazing hair and was all disheveled -- he was running late and everyone was waiting for him. He just came in with this very high energy," she told Cosmopolitan UK in March 2012. "He was just charming, funny and very magnetic. I got his number that night under the pretense of, 'We could just be friends.' And of course, I immediately went home and Googled him."
A year later, she joked to Lucky magazine that the secret to keeping a marriage alive is to not wear sweatpants in front of your partner. "I can't do that to my husband," she quipped, "not after just three years of marriage."