A happily married person may display their favorite wedding photos around their home. On their anniversary, they might just reminisce about all the good times they've had together over the years. Spouses who are not happily married, however, tend to look back differently.

Caroline Madden, a marriage and family therapist and author of How to Go from Soul Mates to Roommates in 10 Easy Steps, told HuffPost that she asks all of her clients how they met and how they fell in love. She then gauges their reactions. She revealed, "It could be tears, laughter or even anger at why they aren't still that couple. What that tells me is if there still is a spark between them, that they remember that they were in love and want to be that couple again."

Sometimes, though, a spouse says they're unable to remember or names things they disliked about their partner from the get-go. Those couples aren't likely to go the distance. She explained, "I can rescue couples from the brink of divorce after an affair — I can't bring the spark back."