What's in the box? Couple's mysterious wedding gift 'best of all'

The instructions were simple.

"Do not open until 1st disagreement. Aunt Alison."

Kathy and Brandon were reminiscing about their marriage nearly 9 years ago while they were talking about an upcoming wedding in Kalamazoo, Mich. they are attending. They were wondering what to get the couple-to-be, and were talking about the wedding gifts they received on their special day.

Then, they remembered "the one."

It was a gift from Kathy's Great Aunt Alison. It was a simple white box with explicit instructions to not open until their first disagreement.

"Now, there had obviously been plenty of disagreements, arguments and slammed doors throughout our 9 years. There were even a couple of instances where we both considered giving up … but we never opened the box," Karen wrote in a Facebook post.

Kathy says the box survived 9 years and three moves, and always just sat high on a shelf in various closets collecting dust.

Kathy assumed the key to saving a marriage was in that box. It had to be, after all, since Aunt Alison and her husband had been married for nearly 50 years.

But, on this night, Kathy and Brandon decided to open the box.

"I finally had a realization. I realized that the tools for creating and maintaining a strong, healthy marriage were never within that box - they were within us," Kathy writes.

She says having that unopened present in the back of their minds somehow taught them about tolerance, understanding, compromise and patience -- because they never wanted it to get "so bad" that they had to open the box.

"That box went beyond what I believe my Great Aunt had intended. It was by far the greatest wedding gift of all," Kathy writes.

So, what was inside?

Two separate notes addressed to Kathy and Brandon, wrapped around cash.

Brandon was instructed to use the money to buy flowers and a bottle of wine.

Kathy was told to "get a pizza, shrimp or something you both like" and to get a bath ready.

Kathy shared her story with the popular Facebook page, Love What Matters.

Her story has been shared nearly two thousand times.

In an email to FOX 2, Kathy says she spoke with her aunt Wednesday night, and that her aunt is just in awe of social media and how quickly news can travel, and how far reaching the story has been.

"My husband and I are actually quite amazed, too!" she adds.

Kathy adds that the box became a running joke at family get togethers. She says they also double checked that there was nothing perishable inside.