Relationships can move in any which direction. They are rarely ever about straight lines, in fact they too can be indicative of a departure from reality much like abstract art.
I was speaking with a colleague this past Wednesday afternoon about the duration of her marriage; 39 years to be exact. And of course, I asked the obligatory question that everyone seems to ask when hearing of such a lengthy commitment foreign to my generation, I promptly blurted out: "What is your secret?" In response, she smiled and laughed out loud, "it is about trusting and tolerating the other."
It made complete sense. If you trust someone you are able to live your life freely and allow them to live theirs, not always being together, allowing there to be space and room for separate interests, and friends. In your togetherness you share a life but you also respect one another's individuality. And in tolerance you accept the person for who they are, flaws, habits, the beautiful, the unappealing, in growth and understanding you move forward in life. Throw in communication and that could very well be the formula for a long lasting partnership of any kind for that matter.
There really are no guarantee's in life, but it is comforting to know that with some thought, introspection, and tolerance, any of us could have something that lasts.