Law, you make a good point . . . I'd vary in only one small detail. You say, "which (set of lives) is more authentic and which feels more contrived."
Both the 'vanilla' and the 'lifestyle' lives can be authentic, neither needs to be contrived. They can both be 'real,' even if they are separate.
For us, yes, what we do between the sheets with others, we love our swinger friends. But we also have a very satisfying vanilla life. Just two separate things.