5 reasons couples divorce after many years of marriage

1. Wear and tear 

The process that leads to gray divorce isn't typically a sudden event or trigger, says Stan Tatkin, author of "Wired for Love." 

Rather, it often happens slowly over time. "It's like an unbreakable plate you drop repeatedly," he says. "The relationship develops microcracks inside the structure you can't see. Then it finally reaches a critical mass and shatters."

It's a reason many couples that split late in life say they've simply grown apart. This usually comes as a shock to close friends and family, such as when Al and Tipper Gore separated in 2010 after 40 years of marriage.

An undercurrent of dissatisfaction can happen for a number of reasons, but several dominant themes crop up regularly, says Tatkin. "Often one person — usually the woman — feels she's given up too much. She may have put aside her career as she raised the children. She feels the wear and tear of the relationship because it wasn't collaborative."

2. Age 

Other times age is a factor. A big age difference that was not an issue at the beginning of a relationship may become a problem later in life, Tatkin says. Or people may hit middle-age and crave a reboot. 

Tatkin explains that people go through biological "brain upgrades" at certain times in their lives, including at age 15 and again at 40. "Every time you experience one you want to go back [in time]," he says. 

Starting a relationship with a younger person satisfies this urge for some people. 

3. Boredom 

Steve Siebold, a psychological performance and mental toughness coach and author of "177 Mental Toughness Secrets of the World Class," cites boredom as a factor.

"Being around the same person 24/7, depending on the relationship, can lead to boredom," he says.

In other cases, people stop trying. "You work hard, play hard and take care of business, but you've stopped being the attentive, attractive spouse. You've allowed yourself to become complacent."

4. Money 

Differences in spending habits and financial difficulties may finally come to a head and cause a break-up. 

One spouse may be a big spender while the other likes to save, Siebold says. "The kids' activities, expenses, and college funds eat the family's discretionary cash and you're deep in debt," he notes. 

5. Sex 

Sexual incompatibility can become more pronounced, says Jessica O'Reilly, author of  "The New Sex Bible" and Astroglide's resident sexologist. 

"Hormonal changes that arise with age can cause significant shifts in sex drive. And though every couple of every age experiences differentials in desire, these can become more pronounced with age."

Couples who may be heading down the path to divorce can take steps to pull themselves back with these five tips: 

Put the relationship first 

 You should be about protecting each other in harsh environments and have each other's back, says Tatkin. "You must become experts for each other and protect each other in private and public — and never threaten the relationship." 

In addition, Tatkin says, couples should have a strong sense of why they're together. 

"Know the purpose you serve as a couple," he says. 

Take care of yourself 

Gaining weight, not exercising and dressing slovenly sends a message to your spouse that you don't care anymore, says Siebold.

"Try cutting the carbs, trimming the fat and heading to the gym," he advises. 

Assess your role in the problem 

Before you give up on your marriage, look in the mirror, says Siebold. "If there's a boring person staring back at you, you may be the problem," he notes. 

And if that is the case, Siebold suggests making a decision to create some excitement in your life. Plan a new adventure together, start a new business, learn a language or develop a new skill together.

These activities create new stories and may reignite your passion 

Talk about sex 

Couples who talk about their sexual expectations, changing needs, and vulnerabilities can manage their differences, O'Reilly says. 

"Communication is essential. As your body changes you need to discuss what feels good both physically and emotionally to cultivate intimacy," she adds. 

Talk about everything else, too 

Lastly, Tatkin says you both need to tell each other everything.

That's the only way to work out your problems.