The 26-year-old English singer said in the March 23 issue of Rolling Stone that it was "very easy" to bed the 27-year-old American star's famous friends.
"Taylor's world is celebrity," Sheeran told the magazine. "I was this 22-year-old awkward British kid going on tour with the biggest artist in America, who has all these famous mates. It was very easy."
"I would often find myself in situations just kind of waking up and looking over and being like, 'How the [expletive] did that happen?'" he said.
Sheeran wrote about some of the flings on his 2014 album, x.
Sheeran released his third studio album, ÷, last week, and announced an accompanying tour on Wednesday's episode of Today. He also performed his single "Shape of You" on the NBC morning show.