As OK! previously reported, Trump marked the occasion on Monday, June 14, with son Donald Trump Jr., his girlfriend Kimberly Guilfoyle and footballer Herschel Walker, among others. According to a source, he was expected to play some rounds of golf, while "the family will celebrate Donald's birthday together as they usually do."
Donald Jr. shared a clip of a "Happy Birthday" singalong with Melania, 51, and Barron noticeably absent.
"It’s always nice when family and great friends as well as a few members of Congress sing you happy birthday🤣. As much as 45 doesn’t love birthdays it was great to be there," the 43-year-old captioned the post.
The video — in which Donald Jr. panned around the room to show the crowd singing to his father — led users to ask about the former First Lady's whereabouts.
"Where's Melania?" one user asked.
"Has anyone seen her ? Anywhere?" another pondered.
"I don’t really care. Do you?" one joked, in reference to a jacket she once wore with the same slogan.
Whether Melania was in attendance during a more private celebration remains to be seen — however, the former model opted not to commemorate her husband's milestone birthday on social media. In March, she marked her son's 15th birthday by sharing a dark photo of black balloons with the caption "Happy birthday BWT❤️❤️❤️." The post went viral after Melania was slammed for what many believed to be a bizarre tribute.
"Melani[a] dear, you could have found a more cheerful pic. This looks quite morbid, but perhaps that’s how you/he feels," one user noted at the time.
"Happy birthday to Barron, but using black numbers for a 15th birthday strikes me as rather odd," another said.
While Melania and her husband's relationship has been under scrutiny since they exited the White House, a source spilled that she "has a good life and knows it," adding that although she "is usually near her husband in some capacity, she keeps her own schedule and leads her own life."
"She has their relationship down to a science," a source previously told PEOPLE of the family unit since they relocated to Mar-a-Lago. "She does what she wants and also continues as Mrs. Trump, so it's unlikely to expect much out of the order at this point."
As OK! previously reported, Melania is said to be "happy and relaxed" since her husband's term came to an end, with sources close to the mom-of-one spilling that she is living by her own rules and "is not beholden to the norms of conventional post-first lady duties," such as releasing a memoir or making public appearances and speeches.