For more than 40 years, New Jersey’s Bill Bresnan has been scribbling love letters to the “beautiful blonde” whose appearance “struck him like a bolt of lightning.”

Sharing the secret of the enduring love he shares with his wife Kirsten, Bresnan says – that in part – it’s the infinite amount of “expressions” that have been delivered more 10,000 times.

Keep reading to learn about the magic that’s safely stored in 25 boxes in the Bresnan’s attic!

In 1974, Bill Bresnan was standing at the front of a classroom, preparing students to be licensed in the securities industry when a “beautiful blonde” grabbed his attention.

“She was this beautiful Northern European woman who struck me like a bolt of lightning,” Bresnan tells ABC News of the first time he saw Kirsten.

He later writes in an essay, “It didn’t take long for an even more serious attraction to develop.”

Not long after meeting in class, the two started spending more time together, exchanging “notes, drawings and little scribblings’ on paper napkins over coffee.”

And then, coffee became dinner and “scribblings” turned into thoughtfully composed cards and letters.

“Into her scrapbook they went, and the collection took on a life of its own,” Bresnan shares.

Over time, their relationship only grew stronger and after their small wedding in New Jersey, Bresnan continued writing his wife love letters.

Treasure trove of love

In 2015, Bresnan and “Krissy” as he calls her, celebrated their 40^th anniversary by reliving a lifetime filled with love and passion.

“Every day – 365 days per year, each year – I write to my wife,” Bresnan writes.

The couple opened 25 boxes in their attic, a treasure trove of sentimental writings from Bresnan to Kirsten, each letter signed with “I love you madly, my Darling” followed by two kisses and an infinity symbol.

There were more than 10,000 letters neatly filed in those boxes.

“They’re essentially a love diary. For example, I could pick out a day in 1982, and it’ll begin with the restaurant we ate in or a movie we saw and then a reaction to that,” he tells ABC News.

The adoring husband never missed giving Kirsten a card, and even when apart, Bresnan mailed postcards or wrote letters in advance.

“My biggest fear now, given my age, is forgetting, but luckily I’m still pretty sharp,” said Bresnan, who in 2015 was 74. “I’m crazy about her, that’s the only way I can describe it.”

Explaining the two have “never had a fight once” in 40 years of marriage, he says they “might disagree on something,” but prefer to talk “than argue.”

When asked for his secret to a successful marriage, Bresnan replied, “The key to any relationship is that you both have to work at it every day…And never go to bed mad. Talk about everything. Everything should get resolved before your goodnight kiss.”

He adds, “I see youngsters at restaurants sitting across from each other buried in their screens but never talking or looking at each other. I want them to enjoy the time they have with each other and treasure it.”

Unfortunately, the Bresnans don’t have any social media accounts so we’re unable to offer you any updates on how they are doing today.

Wherever they are, we’re sure they are together, expressing the continued love they will forever share.