After about three years together, the Spider-Man star and his model girlfriend reportedly broke up... months ago.
Dieteman confirmed the news on Instagram Monday after reposting a Valentine's Day slideshow pro surfer Koa Smith dedicated to her.
"Happy Valentine's Day to my bessss fwennnnnn!!! Love you, baby! @tatianaadieteman," Smith captioned the loved-up pics of the pair.
The model's photo from her Instagram Story was also taken from her boyfriend's photoset, and called him "my valentine."
The now-couple were first seen together in several shots from a trip to Yosemite National Park this past October.
Maguire and Dieteman were first romantically linked in 2018 and kept their romance pretty low-key outside of a few sightings together ahead of the COVID-19 pandemic.
The former couple attempted to keep their relationship away from the public eye, as they were rarely spotted on outings.
In 2016, Maguire and Jennifer Meyer announced their separation after nine years of marriage, and she filed for divorce in 2020. Tobey and the jewelry designer share children Ruby, 15, and Otis, 12.
Despite the split, the former couple has maintained a solid relationship, as Maguire attended Meyer's jewelry launch in late 2017 and even posed for photographs with her at the event.
"They have remained very good friends and are great co-parents to their children," a source told at the time. "They really get along and want things to be as normal and amicable as possible."
Maguire is best known for the Spider-Man trilogy from the 2000s. He has mostly focused on producing in recent years, although he voiced a role in 2017's The Boss Baby and is set to appear in director Damien Chazelle's star-studded 2022 movie Babylon.