A nontraditional relationship isn't likely to hurt Swinton's public image. The actress isn't a huge name in the United States, and she has a reputation for making bold, quirky career choices.
"It's much the same as when Cynthia Nixon came out," E! online columnist Ted Casablanca said of the "Sex and the City" co-star revealing her homosexuality. "When a supporting star does something that is eyebrow raising, it has less of an effect as when a leading star does it. It's Tilda Swinton — no offense, but it's not exactly Julia Roberts going off with some other dude while Danny [husband Daniel Moder] is at home taking care of the kids."
And an open relationship need not be a tumultuous one. It's very possible that Swinton and Byrne can be "the best of chums," as he said, even if she's gallivanting around town with another man.
"We assume, if somebody has two partners, that they must be at each other's throats and competing, and that's not true at all. It's actually very rare. The reality is a lot easier than the fantasy," Easton said.
"This could just be a relationship of convenience. He could be as neutral about her having alliances with other men as he is about a business deal," Marshall added. "All relationships are arrangements. Some are sexual arrangements, some are marital arrangements, some are financial arrangements. And as long as the arrangements are agreed upon by both parties, that's all that matters."
But in a town where back-stabbing is sometimes a business necessity and image is everything, Casablanca predicts a thorny ending to Swinton's alleged three-pronged love story.
"It's like a threesome. Someone's not getting what they want," he said. "The person who is getting what they want is Tilda. And now that she's got her Oscar nomination, she's probably thinking about getting into foursomes."