Taylor Swift's wedding was bittersweet ... her favorite teacher reportedly died the same day she married Travis Kelce.   

According to The Telegraph, Kirk Schwabe passed away after a battle with cancer on July 3, when the pop star got hitched to the Kansas City Chiefs tight end.

Schwabe was a cop in Chicago before landing a job as an educator at Hendersonville High School in Nashville, where he taught criminal justice to Taylor from 2004 to 2006, the Telegraph said.

Schwabe reportedly gained the trust of Taylor and her family, who, in 2009, asked him to be Taylor's personal security guard as her music career skyrocketed. Schwabe jumped at the chance, retiring from his teaching gig and working long, hard hours for the 14-time Grammy Award winner.     

In a recent interview with the Telegraph, Schwabe said he ultimately quit the security job because he was totally burned out, yet he still loved Taylor and called her a "superstar."

Although he was unable to make it to their wedding, Schwabe said Taylor chose the right husband in Travis, believing she has impeccable judgement. Schwabe's wife, Jane, said Schwabe treated Taylor just like one of his daughters.  

Schwabe was 69.

RIP