Whether or not a couple is married, making a solemn commitment to each other can make their lives better. They have each other for support in the difficult times, and they share the joys of life. Each one has a contribution to make to the relationship, and they respect and depend on those contributions. In the end, they have the best chance to experience a happy long term relationship.
Life has its share of variety in good and bad times, and two people working together as a couple to get through them discover the good times outweigh the bad. People without a partner they can trust find the bad times can be crushing, and the joys are not as memorable without a special someone to share them. There are many factors that contribute to a happy long term relationship, but sharing is one of the basic needs.
Couples who plan to be together for a long time will generally make plans or set out goals for their lives, and they work together to achieve them. The knowledge that a partner is there to help in many different ways makes it easier to believe a goal can be met. Even if a partner cannot contribute economically, emotional support can make a large difference. It bolsters each person in the relationship, and it gives the couple a chance to proceed with less hesitation.
Planning and setting goals will not ensure a good life, but it goes far in assuring that life's challenges can be met. People who are prepared for disasters are more likely to get past them once the trauma is over, and it is easier to do this when a partner is on hand to share it. Even tragedies can be survived if a partner is supportive, understanding and able to assist in any way.