Ben Affleck Gave Jennifer Lopez the Meaningful Necklaces She Wore in Her Bikini Shot as a Birthday Gift

Jennifer Lopez's steamy kiss with Ben Affleck wasn't the only romantic part of her viral 52nd birthday Instagram post.

According to Foundrae creative director and co-founder Beth Bugdaycay, the multi-hyphenate star was wearing a piece from the celeb-loved jewelry line, custom-designed by none other than her former fiancé and current boyfriend. She was excited to see Lopez in the pieces, she tells PEOPLE: "To me, Foundrae is about empowerment and self-expression and Jennifer embodies that."

She also gave more insight into Affleck's selections to E! "With the custom piece Ben created for Jennifer, it clearly communicated their love, but it's also a reminder of their capacity for change and growth," Bugdaycay said, adding that the Foundrae team was "blown away by his romantic gesture."

Bugdaycay also explained to E! that Affleck considered several symbols before landing on a few, including "blossoms [that] are fed with passion and continue to bloom, even in darkness, against adversity ... and [a] thorn is the risk we assume for something we love, for living life fully without reserve."

The "Cambia El Paso" singer layered her custom Foundrae necklace with other gold pieces, and wore them all over a red-and-gold bikini and print caftan. Affleck — who shared a kiss with Lopez in one of the her Instagram photos — went a little more low-keye in a navy button-up.

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"5 2 … what it do …💗," she captioned the post, which marked the first time Lopez or Affleck have shared anything about their rekindled romance on their own social media accounts.

On Monday, the Hustlers actress gave fans another loved-up jewelry moment in Monaco, France wearing Reformation's Roarke Linen Dress sundress, sandals, a fedora and a gold necklace spelling out "BEN" in block letters.

A Hollywood insider told PEOPLE in last week's issue that the pair "are madly in love" and "the loves of each other's lives."

"They want to do everything they can to make this work," added a Lopez source.

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Lopez and Affleck, 48, originally began dating in July 2002 and got engaged that November before postponing their September 2003 wedding days before the date. They ultimately called off their engagement in January 2004.

They were first spotted spending time together again in April, following her split from Alex Rodriguez.

Since then, the pair have regularly been spotted hanging out together and spending time with each other's children.

Recently, a source told PEOPLE that the two are very serious about one another: "This is not a summer fling."