The 25-year-old English singer admitted in the March issue of British GQ that he and Swift can be over the top because they weren't popular in high school.
"There's an underdog element to it," Sheeran told the magazine. "Taylor was never the popular kid in school. I was never the popular kid in school. Then you get to the point when you're the most popular kid in school -- and we both take it a bit too far."
"She wants to be the biggest female artist in the world and I want to be the biggest male artist in the world. It also comes from always being told that you can't do something and being like, '[Expletive] you. I can,'" he added.
Sheeran and Swift developed a close friendship after meeting in 2012. The "Shape of You" singer previously discussed his relationship with Swift in 2015, telling Billboard he often spends time with the star and her "squad" of celebrity pals.
"It's quite a weird thing for the No. 1 and No. 2 biggest-selling artists in the world to be close friends," he said at the time. "I don't think that happens a lot."
"[I'm] of course [invited to events with Swift's friends]," the star added. "It's not a vaginas-only club."
Sheeran will release his third studio album, ÷, on March 3, which includes the singles "Shape of You" and "Castle on the Hill." Swift celebrated the songs this month on Instagram, writing, "OH MY GOD OKAY ITS HAPPENING EVERYBODY STAY CALM."