The private couple -- who recently announced that they're engaged, just a few months after revealing that they're expecting their first child -- have been romantically linked for over a year, and have managed to have no shortage of sweet moments in that time.
Keep reading for all the ways the pair shows their love for one another.
He sweetly blushed about their romance to ET
In December 2018 -- following their first sighting together in October, multiple PDA outings and some unquestionably flirty social media comments -- ET's Lauren Zima caught up with Kazee, who adorably blushed over his new relationship, though he played coy with the details.
"I'm very happy at the moment, it's a good holiday right now. It's a good Christmas this year," he said. "You know, it's a very good holiday this year. I've had my birthday -- Oct. 30 -- so I get sort of Halloween, Thanksgiving, Christmas, it's been perfect this year and that's all I can say."
She loves watching him perform
Also in December, Dewan stepped out to support Kazee's performance in Love Actually Live in Los Angeles. At the time, an eyewitness told ET that Dewan sat near the front row during the performance at The Wallis Annenberg Center for the Performing Arts, adding that she teared up during a few scenes. At curtain call, Dewan was seen smiling and applauding from her seat and, at the very end, Kazee blew a kiss, the eyewitness says.
At the after-party, ET’s eyewitness revealed that Kazee came into the room and approached Dewan from behind. The two hugged and shared a smooch. The eyewitness said that after the kiss Dewan wiped her lipstick off Kazee’s face. Kazee was also seen hugging Dewan’s mom, Nancy Lee Bursch, and her step dad, Claude Brooks Smith, was also there.
They share their interests with each other
During an April appearance on The Ellen DeGeneres Show, Dewan told guest host John Cena about a "very intense year [with] a lot of change," likely referencing her split from Channing Tatum, which she announced in April 2018.
While typically very private about her relationship with Kazee, Dewan did share how her 43-year-old actor beau made her into a massive WWE fan.
"Steve, my boyfriend, is a huge wrestling fan and he got me, like, so into it. So much that I watched WrestleMania by myself," Dewan, 38, told Cena. "He wasn't even in town and I watched WrestleMania  because I had to know if Becky Lynch was going to beat Ronda Rousey. I was by myself, I ordered it... I was sitting there, like texting [him], 'Do you know what's happening?' I had to! I had to know. I was hooked!"
She finds 'peace' with him
While Kazee first publicly posted about Dewan in December 2018 -- once for her birthday and again following the death of her dog -- and added another post months later in honor of Valentine's Day, Dewan first made things Instagram official this June.
In the adorable photo, Dewan sported a floral dress as she rested her head on a grinning Kazee's shoulder. "Speaking of peace....❤️," Dewan captioned the sweet shot.
He helps her with her career
ET's Keltie Knight spoke with Dewan in August in the midst of her preparations for Soundtrack, an upcoming modern-day musical drama series for Netflix, and she revealed that Kazee had been "very helpful" with her latest venture, thanks to his Broadway background, which includes a Tony Award for his role in Once.
"You know what, he did give me some little tips and hints there, because it was my first musical experience," Dewan said, adding that "things are great" with her man.
"So, yeah, he was very helpful," she added.
She thinks he's 'a gift from above'
In an Instagram post announcing her pregnancy, Dewan gushed over Kazee, calling him "a gift from above."
"Becoming a mother is quite simply the absolute best most incredible thing that has ever happened to me ?," Dewan said, referencing Everly, her 6-year-old daughter with Tatum. "... I couldn't be more excited to be expanding our family together."
He loves her daughter, Everly
View this post on Instagram
Well...the news is out. I can’t even begin to describe the feelings that I have had since we first learned that Jenna was pregnant! I have waited my entire life for this moment and couldn’t have found a better person to build a family with. The past year and a half has brought so many things into my life that have filled me with the deepest of gratitude. A partner who radiates love, warmth, and kindness. A partner who has faced some of the hardest moments life can deal you with grace, humility, and a desire to learn from the ups and downs. A partner who is continuously growing from those lessons and who supports my growth as a person with love, unwavering support, and understanding. Jenna also brought with her one of the greatest gifts one could ever imagine...her beautiful daughter. Evie burst into my life like a supernova and has continued to burn so brightly in it. I have learned so much about parenting already from watching how amazing Jenna is with her and Evie has taught me so much about what it means to love and communicate with a child and I can’t wait to give her a sibling and make our little family a little bit bigger.
Kazee's post about Dewan's pregnancy news spotlighted his girlfriend's "love, warmth, and kindness" while praising her for handling "some of the hardest moments life can deal you with grace, humility, and a desire to learn from the ups and downs."
In addition to his obvious love for Dewan, Kazee also celebrated Everly in his sweet note.
"Jenna also brought with her one of the greatest gifts one could ever imagine...her beautiful daughter," he wrote. "Evie burst into my life like a supernova and has continued to burn so brightly in it."
"I have learned so much about parenting already from watching how amazing Jenna is with her," he added. "And Evie has taught me so much about what it means to love and communicate with a child and I can’t wait to give her a sibling and make our little family a little bit bigger."
The pair have 'a lifetime to love'
Dewan took to Instagram on Feb. 18 to announce that they had taken the next step in their romance and gotten engaged. The actress captioned a romantic snapshot of herself and her new fiancé, "A lifetime to love and grow with you...you have my heart."
Meanwhile, Kazee shared the same heartfelt pic, along with some romantic lyrics from the song "Let It Breathe" by the Water Liars.
"When you wake in the morning I will kiss your face with a smile no one has ever seen," Kazee wrote. "When you wake in the morning I will kiss your eyes and say it’s you I have loved all these years."
For more with the happy couple, check out this video: