A relationship will only grow if both partners lead balanced and full lives independently.
Why do couples break up? What makes it stop working? Turns out, it can all be traced back to one reason. How does a couple deal with change? How much independence is needed and why does it vary so much for everyone?
Think of our needs (mental, physical, but most especially emotional) as an empty glass. One person cannot fill this glass 100%, nor is that healthy. A relationship works if both people need each other equally. Keep in mind that people are different, so not everyone has the same size glass. Sizes can also change as a person changes. But as long as partners are lacking roughly the same amount, it can work. Couples need only be concerned with the void; it is up to individuals to fill the rest of their lives accordingly.
At the beginning of a relationship (the honeymoon stage), the rush of new love is enough to fill a very big portion of the glass. As time wears on, however, that excitement fades (complacency sets in), leaving a feeling of more emptiness. In order for emotions to remain fulfilling, other relationships (friends, family) and activities (hobbies, work, etc.) must rise to make up for that emptiness. That’s why it’s so crucial to balance friends, school/work, and extra-curriculars accordingly.
If one keeps relying on a partner in the later stages to feel as whole as at the start, discontentment will surely settle. This is often the cause for cheating: instead of turning to personal growth to fill the hole that one person can no longer be enough for, one turns instead to find other people. Likewise, many marriages fall apart after the kids have all left home because there is a hole that spouses are suddenly expected to fill single-handedly.
Studies have shown that single people are often more successful in life. Without a partner to fill a part of the glass, they devote more time and energy into work, and get more out of it in return. Many single people also state that they are content alone because there is no need and no room for another emotional commitment. A relationship (although worth it) does require some sacrifices. It’s all about how one personally chooses to fill their quota.
A relationship ends when one partner, or both, feel insufficiently or over-sufficiently fulfilled. A change of setting (i.e. university, a new job, etc.) can cause over-stimulation, resulting in less emotional need for a relationship. A lack of activity causes boredom and unreasonable demands, resulting in frustration and disappointment in the relationship. So when it comes down to making relationships work, a lot is based on the individuals (not the couple as a unit) gauging how much of the glass is empty. As long as both can adapt accordingly with changes, and keep the need proportionate to one another, relationships will stay healthy.