Now that she is entering her 40th year of marriage with American evangelist Rick Warren, Kay is going on a trip down memory lane and recalling the early years of "marital hell" with Rick and how they overcame the bumps that almost ruined their marriage.

They were barely 21 when they got married, shared Kay, and even though they thought they were incredibly mature going into marriage, they realised that they were actually far from it, she wrote on her Facebook page.

"We quickly learned just how immature—and broken—we truly were," she said. "Rick was a well-known youth evangelist and was currently a youth pastor; we felt intense pressure to have a great honeymoon and a great marriage."

They were miserable during their honeymoon and argued about almost everything. They feigned happiness when they went to church, but deep down, they were suffering from "marital hell."

"We loved Jesus and we were pretty sure we loved each other—so why were we so miserable? Why did we both secretly wonder if we had just completely ruined our lives by marrying the wrong person? Divorce was not an option to us—it was the mid 70's and Christians just didn't get divorced—at least not in OUR families," Kay further wrote.

Things were so bad that Rick was in the hospital for around three months due to depression, while Kay nearly had a complete mental breakdown because they were living a "lie." Still, they both refused to get a divorce.

Now, things are starkly different for the couple. "I couldn't help but stand outside of myself and be astonished at how far we two stubborn mules have come. Instead of trembling anxiously as we did 40 years ago, this time we confidently held hands and repeated vows of love, faithfulness, forgiveness, grace, acceptance and HOPE—confident because our marriage has weathered some of the worst moments any marriage can endure and left us deeply, deeply loving each other," she said.

Kay said other couples might share sweet love songs and have a history that isn't as chaotic as theirs, but that's okay. She appreciates the fact that "two stubborn mules yoked together with bonds," and that for her holds infinite sweetness.