The Australian champion swimmer, who attended the British royal wedding earlier this year, said that he has been in long-term relationships with women in the past but people still think that he is gay.
Thorpe told New Idea magazine: "I don't think anybody has a right to write about [my private life], but I don't care enough about it to be bothered. If you try and fight it, you're damned; if you don't, you're damned. If you get married, it's a sham."
The multiple Olympic and world champion has previously alluded to a relationship with fellow swimmer Amanda Beard. In 2007, he was quoted as saying: "I did have a long-term, long-distance relationship [with Beard] and it was great while it lasted.
"It was sort of public knowledge we were seeing each other, and yet not. It went on for ages, years."
Former Olympic champion Beard, however, has previously insisted that she was never Thorpe's girlfriend, saying: "Take out the word relationship and put in the word friendship and that's exactly what it was."
She married photographer Sasha Brown in May 2009 and the couple have a 1-year-old son, Blaise Ray Brown.
Thorpe revealed last year that he would be launching his television career with a new "lifestyle-based" show. Earlier in 2010, he made his acting debut in a one-off performance of David Williamson's play One Night Only In Emerald City to raise money for charity.
Watch Ian Thorpe announcing his return to competitive swimming earlier this year below: