Q: What should you do if you see someone's fiancé on Tinder?

A: This catapults us onto ethical thin ice. On one hand, we feel the moral duty to "be a friend" by sharing vital information that affects the friend's current and future happiness. On the other hand, we're cracking open a touchy issue that could blow up in our faces and terminate our relationship.

One way to broach the subject is to reveal the information as though it's a coincidence. "This is so weird. There's this guy on Tinder, and he looks just like Jamie. I mean, it's uncanny. Maybe everyone does have a double in this world."

Offering the evidence depends on your friend's reaction to your information. If you feel comfortable doing so, open the app and show the "uncanny resemblance" to your friend. Or, you can include a screen shot via text or e-mail.

Either way, you've satisfied your moral duty while avoiding a direct accusation.

SUSAN WINTER, relationship expert and author of "Breakup Triage: The Cure for Heartache"

A: Ask yourself a few questions before you alert the world at large about this perceived ick. How well do you know the couple? Are you sure they didn't split up and just haven't announced it? Have they chosen to have an open relationship?

If you know the relationship is neither open nor finished, then you have to examine your relationship with each person involved. If you're closer to the Tinder-seeker, I say it's fair to send a message saying, "Seeing you here is weird. Anything you want to tell me?" If you're closer to the other person, let that person know what you saw.

I know: It's someone else's relationship, and we shouldn't meddle, but one of these yahoos gave up the right to discretion and privacy by putting a profile on a dating app. Pretending you never saw it leaves you in a very awkward position whenever your (unaware) friend talks to you about wedding plans.

If you aren't particularly close to either of them, maybe just decline the wedding invite and be supportive when it inevitably unravels. Or get them something they can easily split, like towels.

CORBETTE PASKO, actor and freelance writer