by Ann Brenoff, Senior Columnist, The Huffington Post

We asked our happily-together-for-ages friends to spill their secrets.

​On the cusp of Valentine's Day, we asked our happily-together-for-ages friends what their secret to staying coupled has been. Actually we asked them to tell us which behaviors they avoid -- what are the things that successful long-term couples don't do? Here's what we heard:

1. Spend all their time together.

   ​They do not spend 24/7 together. They develop friendships and interests outside the confines of their coupledom and pursue them with their partner's blessings. Not being together 24/7 is a good thing for a relationship. This goes beyond the "absence makes the heart grow fonder" cliche. When you both have friends outside the relationship and aren't afraid to go off and spend time doing the things you want to do, you bring more to the table. You have things to talk about, experiences to convey. It's a healthy thing to spend time apart.

   David and Claire may be an extreme example of this. They are married yet choose to live seven miles apart. The truth is, you and your mate don't have to like all the same things. Really, you don't.
2. Let the kids divide and conquer.

   Yes, kids will do that. When Mom says 'No," they appeal to Dad. The family unit is strengthened when a parental united front is presented. It is unfair to let one parent be the "good" parent and have all rules and discipline administered by the other parent.

   Kids, little buggers that they can be, understand the divide-and-conquer dynamic and aren't afraid to use it. Don't let them. Be on the same page, even when you aren't really. Disagree behind closed doors but wear the same public face. And this advice isn't limited to your young children. Be unified when your adult daughter asks you to pay for your granddaughter's summer camp or your grandson's ballet lessons.
3. Mistake jealousy for a measure of affection.

   When you see your partner chatting up the new neighbor at a block party, where do your thoughts go? Just know that jealousy is not a measure of affection; it is a measure of your own insecurity.

   Nobody likes to feel distrusted. And truth is, nobody likes to feel distrustful. It's a horrible feeling that leads you to check his or her cellphone, pry into emails, and check credit card bills for charges you don't recognize. (OK, maybe that's a good idea, but do it as an identity-theft precaution and not because you think your spouse is dumb enough to charge the motel to your credit card.)
4. Forget that what's small and inconsequential to you may not be to your partner.

   If it's important to your spouse that her mother like you, make it important to you too. This is one of those areas where you get a trophy for trying. Send your mother-in-law a card on her birthday, just show up to shovel her driveway when it snows, offer to pick her up and drive her to her grandson's baseball game even when she lives in the opposite direction.

5. Stop working at it.

   There is no magic dust that makes people get along. There are, however, some ground rules. Think before you explode. Talk before you implode. Compare less and be grateful more. Strive to make your mate happy. Things fall apart if the ground rules are changed without warning.

6. Consider divorce as an option.

   Many successful marriages are based on this one premise: The commitment that is made is as much a commitment to the idea of the marriage as it is to their partner. When the divorce door is nailed shut, everyone is trapped inside and it just makes sense to try and make things better. Long-time married couples tell us that they stop themselves before they scream seriously unkind irreparable insults. They learn how to forgive and ask for forgiveness. They actively practice gratitude, even when they have to think long and hard for things to be grateful about.

   Nobody ever said marriage was easy. Or necessary for everyone. Or without moments of regret. But divorce, say some long-marrieds, is for quitters.