Alexander returned to social media with a video of himself holding up a colorful arrangement of flowers, tagging the Gimme More singer, 40, in his post on Monday.
"Hand [picked] for @britneyspears," he captioned the video, playing Kanye "Ye" West's song Love Lockdown in the background of his clip.
Alexander also shared a new Reel with the message, "I love haters."
He nodded his head in approval and put on some sunglasses as the audio said, "I show them nothing but love ... If you're not getting hated on. You ain't doing s— right. You need people talking about you. You need people saying 'I don't like that person.'"
Alexander's posts came as the chart-topping performer announced she would be taking a social media hiatus less than a month after revealing she is pregnant with baby number three.
Spears is expecting her first child with fiancé Sam Asghari, having shared the exciting news after a judge terminated her 13-year conservatorship last November, writing, "So, I got a pregnancy test…and uhhhhh well…I am having a baby."
The Circus performer is already mom to sons Sean Preston, 16, and Jayden James, 15, from her previous marriage to ex Kevin Federline.
Spears and Alexander famously got married back in 2004. The childhood friends said "I do" at the Little White Wedding Chapel in Las Vegas, and their surprise union was annulled only a couple of days later.
During her conservatorship battle, Alexander was an outspoken proponent of her freedom and supporter of Spears being able to make her own decisions. In August 2020, he joined fans at a #FreeBritney protest.
"She's ready for this to be over with," he told reporters at the time. "It's holding her back."
He has since made headlines for an unrelated stalking arrest. Alexander pled guilty to misdemeanor stalking in January and was given nearly a year of probation. He'll also have to undergo a mental health screening and submit to random drug screenings.