A year after losing my first love, still feeling a lot of pain?

Sorry if this is gonna end up being a long read. I lead a good, satisfying life -- I'm athletic, generally happy, knowledgeable, friendly, musical, energetic, with a ton of friends and a great family. I'm on track to be my class valedictorian; I can really pick whatever college I want to go to. You'd think most people would scoff at me for being unhappy sometimes, with what I have, right? Well I'm in this emotional whirlpool because of my first love. She's an amazing girl and she left me a year ago because I wasn't as good a boyfriend as I should have been, saying the wrong things at the wrong times, pressuring her sexually (but never EVER like forcibly), stuff along those lines. She "stopped seeing the guy she saw in me when we had met." I was in love with her to death, but I had subconsciously taken her for granted, I guess, cuz I thought she loved me too much to leave. My actions reflected that arrogance and she was right to leave. It's what I would do if I were her. So I'm aware that two people have to make a relationship work, but I basically screwed up and she left. That was a terribly depressing wakeup call which made me learn a lot. Now a changed man with some experience, I look at her awesome current boyfriend as what I could have been, which makes me feel like I should have been better. Self-esteem crap - it's funny and ironic that self-esteem with girls is what's weighing me down, me being a pretty confident person in general. Other girls attract me, but I go through this emotional seesaw where, on one side, I want to explore possible relationships with other people, and on the other side, my first love has such an amazing personality and did pretty much nothing wrong that I want to try for her because she's worth it. I do a lot of activities, exercise, and I spend a lot of time with my best friends, which people say to do when dealing with a breakup, but that stuff only temporarily takes my mind off her -- maybe a couple of hours later, I'm on the other side of the seesaw, missing her terribly. Something in me wants to prove myself, to resolve what I did wrong with her, and that's why other girls don't really appeal as much to me in a relationship perspective as she does. It's not like she's not worth it; she didn't do wrong by breaking up with me - it's what she needed to do for her sake, because I wasn't the best for her at the time. I want to show her who I can be - our personalities match so well and I feel like I'm better for her now than I was. My head says I should move on but my heart tells me to go for her because she's someone who has made me so happy in my life and who is so rare and precious. Again, I go back and forth between these two contrasting emotions of moving on and longing, and I don't know which one is real. Help me out please?