In a sweet video, the 51-year-old singing superstar honored her man with a montage of photos and clips set to the classic 1967 Frankie Valli song, "Can't Take My Eyes Off Of You."
The musical tribute featured photos of A-Rod when he was a baby and segued into clips of him as an up-and-coming baseball player when he was a little boy, as well as a snap of him in his Miami Westminster Christian uniform and a shot of the former MLB star in his New York Yankees pinstripes.
Other footage showed the celebrity couple from behind as they walked hand in hand to an event, as well as clips of the two smooching and looking at each other lovingly. There were also photos of their blended family -- Alex's daughters Natasha, 15, and Ella, 12, and Jennifer's 12-year-old twins, Emme and Max -- and a series of vacation and red carpet pics that led up to the song's famous chorus, "I love you baby."
The tear-jerker video ended with a photo of Alex looking dapper in a tuxedo and a message from JLo to her soulmate.
"Happy Birthday Macho," it read.
The World of Dance judge noted in the caption that she was in the studio and watching her future husband on TV and that she only wants to be with him, laughing and enjoying life, no matter where he is.Fans raved over JLo's adorable tribute to her man as he celebrated his milestone day, so far leaving over 597,000 likes and almost 10,000 comments on the video.
"Aww I'm tearing up!" one fan wrote.
"Your love is so inspiring," added a second person. "Happy bday Macho. Jen loves you so much, always seeing in her eyes, and it's so beautiful."
"I'm so happy you finally found your King. You deserve this love," a third follower declared.
"I hope you guys stay together forever that's the only hope we have in this world right about now," remarked a fourth person.
Others said Jennifer and Alex were the cutest couple ever.
Jennifer's post comes three days after Alex shared a loving montage for her 51st birthday, which can be seen here. In his sweet message, the three-time MVP described his future wife as "the greatest partner, the best mom," and "the most amazing performer" as well as a role model and an inspiration.