Things I have learned in 2006:
The importance of a clean break. Being friends with your former partner is an admirable goal, but some distance needs to be achieved before this can happen. Distance is not achieved by talking every day, saying "I love you," holding hands in public, and regular visits to each other's bedrooms. (Yes, it seems so obvious now that I write it out...) Eventually you will find out that your ex spent some time in someone else's bedroom--maybe even while their place in your own was still warm--and while technically they have done no wrong, it can't feel like anything but betrayal.
Violation of privacy never has a happy ending. The next question is always, how did you find out? I am not proud of my actions, but would not have behaved this way if we weren't still involved in each other's lives. I never did this when we were together, but the knowledge that something was being kept from me was too much for me to take. This kind of challenge completely engrosses me and once I get what I want, I have difficulties unlearning random six-character strings.
Love is a fragile thing. It's not something they ever say in movies or songs, they talk about how strong it is and how it will get you through. I think that this is a dangerous illusion that may well have led to many endings. When you are in the grip of love, that first rush especially, you feel as if the bond between you and another person is invincible and that neither of you can do wrong. So you might become careless, score your points off the other if you need to. The fact that there are never ramifications to this reinforce the behavior, and then one day you realize that someone has in fact been keeping score all this time and you've caused more damage than can conceivably be repaired. I guess the truly strong thing about love is that after all of this damage has been done, the wreckage still persists.
There are so many things I wish I could go back and do differently, small moments where I was caught wavering and chose the wrong thing. You can spend your whole life doing that, I suppose, and it will get you nowhere. The only thing I can do now is learn from the past so that next time I find someone who is crazy enough to fall in love with someone as flawed as I am, it won't have to be like this.