In my opinion a primary key to a long lasting marriage – maybe even THE key – is commitment. Commitment to God first and then to each other. Commitment can overcome differences in personality, religious views, sexual desires, intelligence, health, and a host of other things.
Sometimes it takes the commitment of one spouse and the help of God to hold on for a better day. When we stay committed, we emulate Jesus, who promised to never leave us or forsake us.
One of my favorite examples of commitment was an older lady in our church. For years her husband had struggled with gambling, women, etc. She said something like “I decided the house and bedroom were half mine, and I was not leaving my bed.” Later in life her husband came to Christ. I believe they celebrated their 50th wedding anniversary before he died.