No, I’m not talking about when your wife won’t let you go out with your friends or your husband doesn’t let you talk to anyone at the office Christmas party. What I’m talking about is how to indicate possession when discussing a single object that belongs to two people.
If two people own or have possession of one thing, put the apostrophe after only the second name. For example, if John and Mary host a show together, we referred to it as John and Mary’s show.
Other examples: Dick and George’s secret plan (one plan that they devised together), Barack and Michelle’s gift to the Queen (they gave her one gift together), and Sherry and Paul’s blog.
If you’re talking about two separate things that belong to two separate people, however, each name gets an apostrophe, as in John’s and Mary’s shows, and Newsweek’s and Time’s front-page stories (each has its own front-page story).