It all started with a friendly game of football.

And then, three months later, Jeanine and Mark Earnhart were engaged.

Well, there may be a bit more to the story, which Mark Earnhart emphasized is “really true” and “really corny.”

“I just knew she was the one I wanted to marry,” he said before the two had ever spoken to one another.

Now they have weathered 42 years of ups and downs and published a book about relationships called “Marriage Works.”

Their trials and tribulations have been written in the Wall Street Journal and Good Morning America has recently called for an interview.

But lets go back to the beginning.

In 1968, Mark Earnhart saw Jeanine, then Henley, in the halls of their high school in California and thought, “Wow,” not just because of her good looks, but what he attributes to a chemical reaction, you either have or don’t have with someone.

Henley, on the other hand, had no idea who he was and later that year, when her father passed away, she moved to Alaska.

Earnhart did not forget her and one day in homeroom he discovered a classmate writing her a letter.

“Tell her you’re sitting next to the man she’s going to marry,” Earnhart told him.

A few months later, Henley returned to California for a visit. At a party Earnhart made his move, by tackling her during a football game and the rest is history.

“I still have that letter,” Jeanine Earnhart said.

In some ways that story has kept their relationship strong.

Mark Earnhart tells the story often and it reminds them of the spark that ignited their relationship. And even during a separation they looked to the past for guidance.

The Wall Street Journal’s “To Save a Marriage, Split Up?” focuses on this period when the couple separated and how they fell in love again through long talks in the evening over a bottle of wine and time on their own to reflect.

“When you’re apart you start going back through memories and cataloging good things that only the two of you had shared,” said Jeanine Earnhart.

Before their separation, the couple started writing the book.

Sometimes they found the process of writing therapeutic, but during rough times when they weren’t talking to one another they doubted if they were qualified for such an endeavor.

“Then I thought, ‘Everyone has problems like us and that’s why we should write the book,’” said Jeanine Earnhart. “I had read books from experts that had been married three or four times and I thought. ‘What do they know about marriage?’”

The Earnharts make it clear they’re not experts, just two people with 42 years of experience who have made their marriage work.

They have two strict rules, not to hit one another and not to cheat, but they have issues like getting irritated or not communicating correctly.

They leave each other notes when they get frustrated or when they want to apologize. They also leave each other notes just to say something nice.

Jeanine Earnhart is a night owl and Mark Earnhart is a morning person, so before work, he leaves her notes saying, “Have a good day,” and when she travels he always leaves a “I miss you” note in her suitcase.

“It’s the little things that keep romance alive,” he said. “When you ignore the little things that’s when things break down and then it’s hard to get back on track.”

Their book cover, designed by Jeanine Earnhart, depicts gears moving mean to say that marriage is work.

“It’s not ‘Leave it to Beaver,’” said Mark Earnhart.

When the Earnharts married after a whirlwind romance they hadn’t considered what roles they would fill.

“I cooked for the first 30 years of our marriage and realized I didn’t like cooking,” Jeanine Earnhart said. “Mark started cooking and he makes gourmet meals much better than I ever made. I fix the toilet and change the light bulbs.”

“We both change the light bulbs,” her husband added.

They both agree that over the years, they’ve had more good days than bad.

“We’re stronger than ever now,” said Mark Earnhart. “We’re best friends.”