Being married over 40 years has been the most life-changing, spiritual growth we could have ever gone through. You finally learn that God doesn't send you someone to "meet your needs" (that's His job). He sends you someone you can practice (painfully at times) acting out the fruits of the Holy Spirit which develops and strengthens those fruits.
You all know what I'm talking about: We have had to endure some personality clashes, forgive the worst sins against each other, have patience with each others faults, absolutely keep no record of wrongs, always believe that God is working on the other person, and love unconditionally. To put the other person's needs before your own.
Everything I mentioned totally went against our very natures which are selfish. But there is really a payoff when you see the other person begin to change and grow spiritually as the fruits of the Holy Spirit are given to them through you.
We had to choose to work and act on what the meaning of love is - but when we did, it was like Christ, himself, took it further and began to change us. We had thought it would change our marriage or change each other. But the biggest change was in ourselves.
I don't even recognize the little girl who just turned 17 when she got married.