Thanks, I appreciate that. I read your whole post and have to say, the fact that you're able to be introspective about it, to actually go back and analyze things, and perhaps admit areas where you've been at fault, is actually critical to your progression (evolution, even) as a human being. There are many people your age who don't even attempt to sort out who they are as an individual, or strive to better themselves on a personal level (which, again, is fine; they also cannot fail to accomplish that which they've come here to do). So the fact that you're asking questions and at least attempting to make progress is really phenomenal.
As far your romantic endeavors go, I'm rather reminded of the law of Karma, which many people misinterpret or have a distorted understanding of, but which simply says that Karma cannot be 'overcome', it must be 'worked off'. In other words, if you've hurt someone, be it physically, emotionally, or however else, you will have to, at some future point, experience what that felt like for them. The Law of Karmic Effect is not a 'punishment', it is a tool of learning, which is set in place to promote personal growth and development. If you have to feel the consequences of your actions, there is a higher likelihood of your choosing a different course, the next time around. It is also important to hold in mind that it works both ways. Seek therefore to ensure that the effect of your presence upon those 'others' whom you encounter upon your journey, are positive and beneficial.