Here I describe a few principles of what makes a marriage or live in relationship last. The essay does not describe tips but instead shows how people evolve and how a relationship must evolve if it is to last. It also describes what happens when things go wrong.
People change every seven years
This is a description of most humans but is a generalization. People do change at points in their lives, but the change is only an average of every seven years. Some people change frequently at some points in their life and then more slowly later on, and the opposite is true too.
People change as some sort of biological process, though not enough study has gone into it to prove it is not biological. You will notice that people tend to change jobs, lovers and their situation at a rough pace of around every seven years. The people who slog on within a job for longer are often given the chance to switch roles or move up, which is why they do not quit. A marriage however, or a live in relationship may well be “quit” after a period of seven years.
Evolving within a relationship is needed
Each partner is going to change within the relationship. Each is going to change every seven (approx) years. The couple needs to grow and evolve together if the couple is to stay together. This is the only way to survive what is described as the seven year itch. This is where couples start to become bothered by the other person. It requires the people within the relationship and the relationship itself to change in some way. If no change occurs via natural evolution or unnatural evolution (couples therapy) then the relationship will end.
When couples get too comfortable
This is a form of evolution that is quite nasty. It is where a couple become very self-centered because they are comfortable within their relationship. Comfort within a relationship is a good thing, but couples may become too self centered which often leads to an eventual breakdown of the relationship. The most common symptom is that the couple tends to put on weight and care less about their physical appearance.
When the man or woman takes too much control
This is another form of evolution that is not for the best. One partner may assume control over the other. This is a very unhealthy type of relationship and often results in a very nasty divorce or the other person resorting to addiction or cheating. Cheating is often the case when the controlled partner gets a taste for how life may be when he or she is not controlled (it is often all the incentive they need to start cheating).
What you have read is a description of the dynamic within a modern marriage or live in relationship. What it describes is also the need to evolve and change in a healthy way as the relationship progresses. A marriage or live in relationship without this change is doomed to failure.