Kaley Cuoco, who is now engaged to Karl Cook, was previously married to Ryan Sweeting and once secretly dated her The Big Bang Theory costar Johnny Galecki

Kaley Cuoco’s journey through romance has had its twists and turns.

On Thursday, The Big Bang Theory actress got engaged to Karl Cook after nearly two years of dating. Her fiancé announced the couple’s engagement on Instagram, sharing a video of her joyous reaction to the proposal.

Cuoco was previously married to Ryan Sweeting after a whirlwind courtship and quietly dated her The Big Bang Theory costar Johnny Galecki.

Here’s a look back at her most notable relationships.

Johnny Galecki

The Comic-Con Conundrum
Jim Parsons (left),Mayim Bialik, Johnny Galecki and Kaley Cuoco

Cuoco and Galecki’s characters may be married on The Big Bang Theory — in fact, Penny and Leonard exchanged vows for the second time in September 2016 — but they also dated in real life.

Although they kept their relationship a secret at the time for the sake of the show, Cuoco, 32, and Galecki, 42, dated for almost two years from 2008-10.

“It was such a huge part of my life and no one knew about it,” Cuoco told CBS Watch! Magazine in 2010 following the breakup. “It was a wonderful relationship, but we never spoke a word about it and never went anywhere together.”

She added that even though they both agreed to keep their relationship quiet for the sake of the show, the secrecy helped contribute to their breakup. “Everyone was always asking, and we deny-deny-denied,” she continued. “And I’m like, ‘Why am I denying this person that I love?’ ”

But despite the potential awkwardness of having to continue to work together, Cuoco and Galecki have remained close friends. In 2013, Galecki told CBS Watch! Magazine “We’re dear friends, still. Kaley’s not just an ex, she’s a part of my life.”

In fact, they’re such good friends that in March, Cuoco shared a photo on her Instagram of her ex cuddling up to her then-boyfriend Cook.

“Ummmmmm then this happened. @sanctionedjohnnygalecki get off my man!” she quipped with a crying-tears-of-laughter emoji.

Ryan Sweeting

4th Annual Critics' Choice Television Awards - Backstage and Audience
Ryan Sweeting (left) and Kaley Cuoco
| Credit: Kevin Winter/Getty

In September 2013 — just three months after they were first spotted together — Cuoco got engaged to former tennis player Ryan Sweeting.

The couple tied the knot Dec. 31, 2013, at a fire-and-ice-themed wedding, but they decided to split 21 months later.

“Kaley Cuoco and Ryan Sweeting have mutually decided to end their marriage,” Cuoco’s rep told PEOPLE exclusively at the time. “They ask for privacy at this time. No further statement will be issued regarding this matter.”

According to court documents obtained by PEOPLE, Cuoco filed for divorce citing irreconcilable differences. The court documents also revealed that the actress and Sweeting, 30, were separated as of Sept. 3.

RELATED VIDEO: VIDEO: There Was ‘Noticeable Tension’ Between Kaley Cuoco and Ryan Sweeting Before Divorce, Source Says: ‘You Could Tell the Honeymoon Phase Had Ended’

Despite the fact that this relationship didn’t work out, in March 2016, she opened up to Cosmopolitan about how she wasn’t ready to give up on love just yet.

“[What happened] changes the way I look at marriage, and that makes me sad,” she said, though she maintained it “does not change the way that I look at love.”

“I cannot wait to be in love again,” she added.

Their divorce was finalized in May 2016.

Karl Cook

Amazon Studios Golden Globes Party - Arrivals
Karl Cook (left) and Kaley Cuoco
| Credit: Milla Cochran/startraks

Cuoco and Cook — who both share a love of horsesstarted dating in spring 2016 and made their first public appearance as a couple in September that same year.

Asked by PEOPLE in August if she could see marriage in the cards again with Cook, Cuoco said that she was “open to anything.” “I don’t know what the path is going to take,” she said. “But I’m very happy right now.”

And a few months later, Cuoco and Cook got engaged — on Cuoco’s 32nd birthday.

RELATED VIDEO: Kaley Cuoco Is Engaged to Boyfriend Karl Cook

“Well after nearly two years I finally got up the courage to ask her to marry me. This is the best night of my life and I think the video shows it is the best night for kaley as well… of she said yes!” the professional equestrian captioned his footage of Cuoco crying uncontrollably.

“Still crying every part of this night has been perfection just like you @mrtankcook I love you forever!” Cuoco wrote alongside the same video which she posted on her Instagram account.

Cook also shared a close-up shot of the gorgeous pear-shaped diamond ring he presented his bride-to-be.

“I am so so so happy. Thank you @nadis_diamonds for making the greatest ring I could hope for. Absolutely brilliant. Thank you thank you,” he said.

Just hours before sharing the proposal on social media, Cook teased Cuoco with a fake ring while shopping at Target.

“On my loves birthday I got her everything she has always wanted….now judging by her face maybe not, it’s the thought that counts right,” he shared.

Cook had his love in tears even before he gave her the real ring as he treated her to a romantic, candlelit dinner at their home. Cook prepared the meal himself and even made a menu as if they were at a restaurant. He made sure to serve all her favorite foods, including Moose Tracks ice cream.