Hi Porterman,
This is a well-thought out question. You’re right – why do we trick ourselves into settling for a relationship? Back when we were still in tribes, we settled down together because we realized that was a strength over other species – to stay in one place, share our responsibilities of hunting and gathering and later agriculture, expanding the species, avoiding death by traveling / migrating less, etc. Overtime, this settling together became a whole institution of marriage, woven it into religion, into the legal system, and everywhere else. So do we need to settle together? In my opinion, it’s really not necessary in the modern world we live in.
As for the spiritual questions you raise – yes, every relationship brings you closer to your own strengths and weaknesses. The characteristics, attitudes and annoyances you encounter are reflections of yourself. However, that’s not a reason to stay in an unfulfilling relationship. Rest assured, if you haven’t worked out your weaknesses, you’ll encounter them again with the next person you have a relationship with. So you might as well address them with someone you can enjoy a happy relationship with 🙂