A woman is going viral on TikTok for sharing the many ways she honors her husband’s first wife, who died 10 years ago at age 33.

Rachael Knaak has shared several glimpses of her life with husband Atom Knaak on social media — including how she bakes cupcakes every year to honor his late wife, and how his late wife’s parents now serve as “bonus in-laws” to Rachael.

“We met in December 2014, and married September 26, 2015. It was a very quick relationship, but we knew on our first date we were going to get married and it was just natural,” Rachael tells PEOPLE of her love story with Atom.

Their meeting came one year after Atom lost his first wife, Gretchen, when he was just 29.

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When the two met, Atom opened up about how he was a widowed single dad of a then 3-year-old boy named Riley.

“When I came into the picture a year later, I came in with the understanding that she was part of their story,” Rachael says, adding that now, Gretchen is “part of our story.”

Rachael learned early on in the relationship that Atom remained close to Gretchen’s family — a bond that she says she appreciated.

“I honestly loved that he put that much effort into ensuring they got to see their grandson. To me, it showed what an honorable man he was,” Rachael says.

Rachael now refers to Gretchen’s parents as her “bonus in-laws,” noting the close relationship she has developed with them since marrying Atom and having three kids of their own.

“I come from a very close and tight-knit family,” Rachael says. “And I recognized that Gretchen, his late wife, also came from a similar family structure. I think that made it easy to welcome them into our lives and love them.”

Gretchen’s parents, Rachael says, “have always been so welcoming and loving towards me.”

They even attended Rachael and Atom’s wedding and visited “just days after” the birth of their other children: Harper, 8, Myles, 6, and Sutton, 10 months.

“They are proud grandparents to all four of them,” Rachael says, adding that the three children that she and Atom have had together “know no different — they have three sets of grandparents and are very lucky kids to be so well-loved.”

As her own relationship with Atom has deepened over the years, Rachael says she has always made sure to center Gretchen as part of her conversations with both her husband and his son.

“Ensuring Riley never felt afraid to mention her name, ask questions about who she was, and fostering a love for her by being able to celebrate her life on her birthday were all things I just did from the very beginning,” Rachael adds.

This year marked the 10th that the trio — along with Rachael and Atom’s three children — celebrated Gretchen’s birthday without her. Footage of that moment has gone viral on TikTok, amassing hundreds of thousands of views and complimentary comments from those impressed by Rachael’s commitment to honoring her husband’s late wife.

“We sang her ‘Happy Birthday’ and he blew out candles for her,” Rachael says.

She chose to share the moment on social media, she says, because she remembers stepping into a relationship with a widower and feeling she was in uncharted waters.

“I was a 26-year-old woman walking into a very unknown scenario and had no clue what to expect. I knew that loving a widower would come with its own challenges and I would need to approach it with an understanding very different from any relationship I’d been in before,” she says. “Stories like ours were hard to find.”

TikTok videos showcasing her children’s special relationship to their “bonus grandparents,” or showing her family celebrating Gretchen’s birthday, “show other young widows and widowers that there can be beauty and hope from the hard parts of their stories.”

“It’s a very unique and different story than most, but at the heart of it … it’s family. And she’s part of mine,” she adds.