Dating Questions: How do you not become too attached?

In the world of dating, the challenge is to be open to a relationship, share, engage, connect, encourage, support, and seek to understand.  However, not everyone approaches this with that aspect in mind.  But if they do, your friendship will blossom.  As it blossoms...you then experience a new kind of problem.  

How do you do this and not become too attached?  

How do you give of yourself and leave expecting nothing in return?  

How do you enjoy the relationship and want to spend time together, want to communicate you are interested in getting to know them more, and yet give space?  

I believe learning to do this is the art of a relationship that will last...but figuring out the balance is the tough part.  The balance of not becoming too attached.

I like this quote:

Detachment is not that you should own nothing. But that nothing should own you.                                                  - Ali ibn abi Talib

I don't believe a Man should own you.  You need to have energy for yourself to be able to give to the relationship.  If you are too deeply attached, you won't be able to be your own person.

How did you do this when you were dating?  Or if you are dating, how do you do this?  What things do you believe are key components to building a great relationship?