Are we meant to be in long term relationships?

There's something that I've struggled with for a long time. As someone who embraces logic as an important and necessary way of making sense out of life, why do illogical things appeal to us a humans? Is it due to society? Is it from religious teachings? Is it part of keeping up with the Jones's?

This struggle is the question of whether we as humans are meant to be with a significant other for a long period of time,short period of time, or do we just naturally drift from person to person, going through periods of love and happiness, sadness and struggle as our ever changing needs dictate?

It seems to make sense to me that humans, in a nutshell, are mostly intelligent mammals. Most others in the animal kingdom don't select lifetime mates. Why does it seem that we go against needs, desires, wants? Why do we have emotions like heartache, love, jealousy?

Why is it then that when we ARE in love and involved in a mutually satisfying relationship, that it is able to fall apart? When we find someone and are bonded together by common interests, humor, chemistry and the 7 Keys that are instrumental in a successful relationship, how can it possibly end in tragedy and sadness? Why is it that we have a need to have a partner?

Surprisingly enough, one day, I stumbled on a New Jersey divorce attorney's website. It was chock full of everything that I had surmised about being in a successful relationship. You can find this interesting wealth of information here -
http://www.userniche.com/LoveAndDivorce/ASP/UserNicheMainPage.asp?ID=2

One thing that I found was the "7 Keys to a good relationship". It struck a chord with me that makes sense. Despite having all of these things in my last relationship, and it still failed, I've lost faith in the romantic fantasy that I've always wanted and am settling for the life spent alone. It's just not worth the pain that you feel after it goes down the tubes.

Here are the 7 Keys;

1. Maturity – a person' s ability to interact with other people and achieve solutions to problems;
2. Relational Positioning – the relative position on the continuum of maturity that each partner in a relationship to the other partner of the relationship;
3. Chemistry – a biological physical attraction and emotional body language that draws you to the other person;
4. Compatibility – similar likes and dislikes, with no major incompatibilities (Deal Breakers), along with the capacity to move over time into common directions;
5. Equity – since there is no such thing as a perfect match, we have the ability to enter into a “balanced” relationship as long as there is equity. In this sense, the balance of What’s In It For Me for each partner, determines the “fairness of the deal”. However, changes in that relative position of one partner to the other can prove disastrous to the relationship.
6. Commitment – valuing the relationship above your own short term preferences, not as a martyr surrendering your needs, but as a mature adult who takes responsibility for their own actions and desires to find solutions that are acceptable for both parties.
7. Adaptability – as one or both of the partners changes, their internal relationship changes, requiring either no relative internal changes or that each party can adapt to relationship changes or the relationship fails as a result of the Bad Changes.
   
   One thing they forgot to include is COMMUNICATION! This is probably the most important Key of all. If your partner doesn't communicate needs, concerns, things bother them, ect, then we don't have the road map that we need to navigate away from things that can sink the ship.
   
   So, after struggling through relationships, learning from mistakes, researching how to be a good partner, and applying what I've learned, I don't think a relationship is in the cards for me. I had everything that I ever desired in a partner the last time. I honestly thought that we were going to be together for the rest of our lives, considering all of the things we have in common, and the 7 things listed above.
   
   When someone is afraid to confront their own issues, it can have devastating consequences to their partner.
   
   What's your take on relationships/marriage?