How do we decide?

I've spent a lot of time in my life telling myself that I wanted something more. I wanted the next best thing. I wanted the better grade, the better job, the better school. Everything seemed to just be on the verge of something great. Everything. It could have been food, clothes, anything. And it wasn't just me telling myself this, it was all of the people around me; parents, siblings, grandparents, teachers, everyone.

So, I guess it stands to reason that I am 28 and so ready to just throw everything away for no other reason than the grass seeming greener. It seems that one small aspect of my life can be still for just a moment. I can settle into it and let it grow and watch what happens. But, I still have this nagging voice in my head that tells me the next best thing is on the horizon. It's been very difficult to turn it off, and sometimes I can't. Somedays it's so easy. But what I find more difficult is not letting it affect everything else in my life. I can't let it get to the point where I let my life not happen because I want one extra thing in my life. I have to find the balance. But where do I find it?

How do I go from living a life that is so unstructured and unpredictable to trying to have a structured relationship, while maintaining a healthy focus on myself and the career that I thought I wanted? How do I maintain wanting to go away for a few small months, yet continue to nurture someone else and what we are trying to build together? 

I'm sure this comes as no surprise, but I've dated a few people. Just a few. It always ends. I could blame everyone else for not being the one I want to spend the rest of my life with, but I'd be lying. I'm not the person I want to spend the rest of my life with. The problem lies within me. I used to be so motivated and focused on what I wanted. And now, it just isn't there anymore. So how do you find happiness within yourself while trying to keep a relationship going that you know is good? Is there really a way to find it all? 

As a skeptical person, I don't think so, but there's always a little voice of hope in my head.