No pulling the “But I’m/they’re married!” card. You get a free pass with anyone from the past (no one living, that’s a different thread), just the two of you for a few hours. You can hang out at your place or theirs.
If she had been a real person I might go with Helen of Troy, at her place. I’ve only seen how different people have depicted her, but from her reputation she sounds like fun.
In reality (even though it might seem like it a common answer) off the top of my head I’d go with Marilyn Monroe. I’m a fan of the hourglass figure.