Quasi-Romance

For the past few years I have been grappling with this question:  Can true love exist without any verbal expression of commitment?

Normally, the story looks like this: 

Guy meets girl (or vice versa).  

                                                

Guy and girl hit it off for a few weeks or months and eventually become an item. 

Now, there are many people that would argue about the time it takes to commit to someone, but what if its been two years and you're still with someone--but not really with someone. You have suddenly and unexpectedly entered into a Quasi-Romance.

In this situation, usually one person wants to really be in a committed relationship with their partner but their partner "isn't ready" for a commitment  for whatever reason.  For the person who wants the commitment, this type of arrangement is psychologically and emotionally damaging.  The worst part of it is the ambiguity of the whole situation.  How do you reconcile the contradiction of someone acting like a boyfriend to you, but not wanting to be you're boyfriend?  

He/she cooks for you, takes you out, does special things for you on your birthday, goes on vacations with you, and even wants you to meet the parents!  But, at the end of the day, when you confront them about being in a relationship they still answer with a resounding NO.

This type of relationship only caters to one person's needs and not the other, and is unhealthy for the person who wants the commitment. For the commitment-wanting person, it can also be a MAJOR blow to your self-esteem and you find yourself questioning every little aspect of your own behavior or person that may be turning your partner off to you. The best thing to do would be to end this quasi-romance as soon as possible in order to salvage any sense of sanity.

But what about the person who doesn't want to commit? Why engage in years of being someone that you don't want to be with? Does this come from a fear of commitment or trying to play it "safe" for fear of getting hurt by someone you really care about?  I've heard many people who are the perpetrators of quasi-romances say they're just not ready.  However, they ACT like boyfriends/girlfriends to their significant others, and are therefore being contradictory.

Have you ever been with someone you didn't want to commit to? If so, why invest so much in someone you don't really want?