"Jeff would never cheat. He's an amazing man," Haynes wrote. "Please stop being mean to him. The song I wrote was about a past relationship. ❤."
Haynes and Leatham were first romantically linked in February 2017, after Haynes shared a pic of the two embracing in a heart made of rose petals on Valentine's Day. The actor confirmed his romance with the celebrity florist a few days later, and the next month, the pair became engaged.
Colton Haynes and Jeff Leatham Are Married! See Inside Their Stunning, Star-Studded Wedding
The Teen Wolf star's rep told ET at the time that Leatham proposed in Cabo San Lucas, Mexico, with a personalized video message from Cher (filmed during an ET interview), who sang their favorite song, "I Got You Babe." The video included messages from family members and other famous friends, like Melanie Griffith and Serena Williams.
Haynes pulled off his own romantic proposal in May, and the two tied the knot in a star-studded Palm Springs wedding officiated by Kris Jenner. Over a hundred guests watched the pair say "I do," including Griffith, Sofia Vergara and husband Joe Manganiello, Jesse Tyler Ferguson, Lisa Rinna, Chelsea Clinton, Dylan O’Brien, Emily Bett Rickards, Billie Lourd and Cheyenne Jackson.
The two weren't shy about sharing PDA on social media, but have now unfollowed each other. Haynes has also seemingly removed most of his pics of Leatham from his Instagram account.
Haynes couldn't have been more excited to marry Leatham while speaking with ET just weeks before his wedding. Watch below.