In celebration of her husband's 42nd birthday on Monday, June 21, Katherine shared never-before-seen pictures of the pair and a touching caption to her Instagram.
Katherine captioned a photo montage highlighting their happiest memories, "Happy birthday to my love! You're the most amazing husband, a loving father, supportive partner, hardest worker (working on your birthday!), excellent chef and so much more."
"I am so grateful to be living life with you," she continued. "I love you more than you know! Happy happy!"
The series of snapshots showed the couple in various intimate moments throughout their three-year relationship. The first depicted Katherine on her husband's lap, while the next displayed the couple smiling during the 31-year-old's pregnancy.
Their daughter, Lyla Maria Schwarzenegger Pratt, was born in August 2020. Lyla is Katherine and Chris' first child together, while the Guardians of the Galaxy star also co-parents 8-year-old son Jack Pratt with ex-wife Anna Faris.
During a recent appearance on E!'s Daily Pop, Chris opened up about being a father to Lyla and Jack.
"The greatest gift that I've seen so far, the second child really shows you the uniqueness of the first child," Chris shared exclusively. "When you have one child, you just think, ‘Oh that's what babies are like.' And then a second child comes along, and they might do things differently from the get-go, and you say, ‘Oh wow, OK so that was actually unique what my first child had done.' Each child is unique and special and they're not just punched out of a mold."
Katherine's younger brother, Patrick Schwarzenegger, also joined in on the well wishes toward his brother-in-law. Patrick, 27, posted a photo next to Chris, brother Christopher Schwarzenegger and dad Arnold Schwarzenegger all dressed up.
"Happy birthday @prattprattpratt your my 2nd favorite Chris, and always will be," he joked, referencing his brother with the same name. "But seriously you're such a genuine human. You treat my sister so well! and your a great big brother to look up to!"