What is the secret to a long and happy marriage? For Robert Walker and Esther Doby, there are three ingredients to that: going to church regularly, singing, and—unabashedly—enjoying good sex.

Walker and Doby have been married for over 75 years, but Walker can still recall the first time he ever saw his wife while she was walking to church in their Atlanta neighbourhood.

It was love at first sight for Walker, who immediately begged her cousin to set up a date between them. Doby told her cousin, "Tell him I'll give him a date if he'll get a suit [and] come to church."

"So I went and bought me a suit," Walker told KCBD.

In the end, Doby said Walker grew on her and she fell in love with him as well. They eloped on Friday the 13th back in 1942, when Walker was 20 and Doby was 17. After seven months, Walker was required to join the Army during World War II.

"When we went through the war years, I found out what is was to be alone," Doby said. "So when he came come, I just vowed that I wouldn't let the sun go down with us mad at each other."

And she held true to that vow. Doby said having a healthy church life really boosted their marriage.

They also always find enjoyment singing in the car while going on road trips. One of their favourite songs is "Let Me Call You Sweetheart."

Aside from going to church and singing, the couple also mentioned another important ingredient to their marriage. "Well, if you have a good sex life, that helps. I'm sorry, but it does," Doby said.

"We never had any problems, sexually," Walker smilingly added. "That worked out well."

Earlier, evangelist Billy Graham said so many marriages are failing today because people no longer see marriage as a commitment — a commit not only to each other but to God as well. At the same time, Graham said people have a warped view when it comes to love.

"Love, for many people, is only an emotion — and when the emotion fades, so too does their relationship. But true love is also an act of the will — a commitment to put the other person first instead of self," he wrote on his website.

Graham said people need to reassess their thoughts on God and love, and put Him in the middle of every relationship so that they can enjoy true happiness and security.