This has been sort of a secret for years in Hollywood...a porn star/fitness guru helped Travolta back in the '70s and later came out and said they'd had an affair. Now usually when this happens and someone is lying a celebrity can sue them, but instead of suing Travolta paid him off to keep quiet. This indicated to a lot of people that the guy's story was true. More gay rumors floated around for years.
To be fair I don't think he's gay, I think he's bisexual because I know he was really in love with a co-star of his in The Boy in the Plastic Bubble...and she died of cancer and he said it ruined him. But this picture pretty much proves he swings both ways.