Is"wanting what you can't have" true? my gf of 3 years left me?

Hmm, sounds to me like she may have started to feel smothered. My boyfriend and I have been together for 4 years and it is hard sometimes. When we started dating we spent every waking second with one another. As time went on, things in our lives kept changing. I got out of school first, started a desk job. Then he got out of school and started a job too. Each change brings a challenge and can sometimes alter your feelings. We've made it threw it all. Maybe you're girlfriend was starting to feel as if even though she loved you she needed some freedom, since it suprised you, you wouldn't give it to her so you broke up after arguing. I do think that you givign her her space could bring her back to you. She may just need time out on her own to realize that its not really what she wants. My boyfriend emailed me when we had our breif break up. At the time it didn't work and I even told him I couldn't take him back. But, since it was an email, a week later I couldn't stop reading it over and over missing him, I called him, and we've been back together since. Good luck, hope you get her back :)