Liking, interests, necessities, circumstances, greed, pure love and similar other factors would make me establish or get into relationship. Born to my parents is a pure love relationship and that would never change. My wife/kid would get a same relationship from me. Then there would be friends who I would never forget and others who I may not remember. Most relationships have a chance of change and it is how I would manage them. Given all the scenerios, it is difficult to say which one would last longer. Good part is that, as long as it lasts, it does satisfy one of those factors.
Surrender, care, opinions, agreements and disagreements, keeping in mind/ keeping in touch, being honest etc. would be my ways to manage my factors of relationship.
How does it end... well..I could end it or you could do it...Ending must be having many "other factors" which may be extreme side of the ones that started it...I think...