Katherine Heigl and Josh Kelley Celebrate 10th Anniversary With Bathtub Snapshot

12/24/2017 11:45 pm EST

Katherine Heigl and her singer/songwriter husband Josh Kelley are still going strong after 12 years together.

The Grey's Anatomy actress shared with fans side-by-side photos of her and Kelley channeling the Wes Anderson movie The Royal Tenenbaums, in a nude bathtub picture both 12 years ago and today.

Heigl went on to explain in the caption that the first photo had been taken when she and the singer had first started dating as a "random" impulse, but that the desire to be silly with him hasn't waned after 10 years of marriage and three kids.

"A few things have changed since then," said Heigl of 12 years in between the two photos. "I quit smoking, thank God! I've put on a few pounds. I don't often do spontaneously weird things like take random bathtub photos in the middle of the night anymore. But what hasn't changed, is that burning desire in me to be with this man."

The 39-year-old actress admits their relationship isn't perfect.

"I gotta be honest. There have been moments where I didn't think we'd make it. Where I wanted to take my pillow and smother him in the middle of the night," she wrote. "But I'll tell you what. The more time I spend with this guy the more deeply I begin to understand that he is the best of me. When the whole world falls into disarray and nothing makes sense to me he is my shelter, my safe harbor. When self doubt and self loathing creep into my soul he is my champion, my number one fan."

Heigl continued, "He has bolstered my spirits more times than I can count and he has led me through the darkness back into the light even more times than that. In quiet moments of reflection I feel an overwhelming gratitude that I married this man."

The Knocked Up actress also praised her husband's parenting skills, humor and confidence.

"I don't think there's a person who's met him that doesn't love him and I get to call him mine. He makes me better in every way by loving me and believing in me and for never giving up on me," she concluded. "So here's to 10, 20, 40 more years of us! I love you [Josh B. Kelley] more than you can probably imagine and then some!"

The two are parents to son Joshua, who just turned 1 year old, as well as adopted daughters Nancy, 9, and Adalaide, 5, but they might not be finished adding to their family yet.

"I still want more children," she told PEOPLE last January. "I'd get pregnant again, and I still am very inspired by adoption. I also have been thinking a lot about fostering."

Photo credit: Instagram/@katherineheigl

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