NEW YORK(CBSNewYork) — One couple’s 40 year love story has surfaced just in time for Valentine’s Day.

Every single day of their marriage has been documented in love letters. The couple shared their secrets to happiness with CBS2’s Meg Baker.

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The couple has 10,000 love notes filled with endless ‘I love yous.’ Bill Bresnan has written a letter to his wife Kris every day since they met in 1974.

“They weren’t all love letters. They were hilarious, very funny, cute, not all mushy mushy, all kinds,” Kris Bresnan said.

The flirting began when the couple started commuting together.

“And while we were on the Long Island Railroad having coffee together I’d scribble a little something a napkin or write it on the end of a newspaper and that kept developing until I gave her actual cards,” Bill Bresnan said.

Without Bill knowing Kris started to organize the notes by date. The couple calls it their love diary.

“It’s almost as though you know how perfect I was. I know how perfect you are for me,” Bill said.

The couple never goes to bed angry, but also has never really had a major fight.

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“We kiss goodnight and it’s like starting the next morning with a clean slate,” Bill said.

The couple is now screening the letters, deciding which are appropriate to be saved for their four children someday, and gently disposing of notes meant for their eyes only.

“My biggest fear, and I guess this is human nature, as I get older my biggest fear is the day I forget to give it to her,” Bill said.

The key to the couple’s love?

“Do things together, have fun together, love each other,” Bill said.

But for Valentine’s Day, they say keeping it simple is important.

“Sometimes we go out to dinner. Sometimes we cook at home. We started Valentine’s Day earlier, I started giving Kris Valentine’s Day cards at the beginning of February,” Kris said.

One parting piece of advice the Bresnans offered for the younger generation is to put the cell phone down and focus on each other.

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