I am so sorry to hear that you are having such a difficult time trying to understand your feelings. The confusion and distress you are experiencing sounds very powerful indeed.
One thing we here at malesurvivor like to do is stay away from trying to assign meaning to another persons emotions and experiences. It is better if we try to provide as many options as we can, and let you make the decision on your own. Making the decision for ourselves and experiencing/facing the outcome is how we gain confidence. Asking for guidance is a very wise and often essential step in making those decisions.
I always had a feeling that I need to have a mistake... a big one to make myself feel useless and not as perfect so as to be able to understand how people who made mistakes feel... and be able to forgive them.
This sounds like you are saying that you are trying to find forgiveness within yourself. You mention being somewhat of a perfectionist. Perfectionists often have trouble forgiving themselves for being imperfect. Is that something you are afraid of? Being imperfect? I hate to have to tell you this but we are all imperfect whether we want to be or not. You can view this as a curse or as a blessing, but I think you will find that one will leave you full of darkness and fear, while the other is full of enlightenment and freedom. It's your choice to make.
Others here may disagree with me on this next one, but I think some of the answers you are looking for might require you to re-connect with this friend who "took advantage of you". I can't help but think that it sounds like you are running away from what this connection may have meant to you (or at least trying very hard to "push" it away). I don't want to add to your confusion about anything but it doesn't sound like he had the intention of hurting you terribly. Sure, it DOES sound like his decisions and motives were a bit selfish, but the fact that he has tried to re-connect with you in a responsible and mature way suggests that he is sincere.
Are you afraid that seeing this friend again may lead to another regretful event? If so, you might want to try setting up some boundaries. If he respects you, he will respect those boundaries.
On the other hand, if you feel that you cannot trust him then that is another story. If this is the case then contacting him could potentially be harmful to you.
Please forgive me if I sound presumptuous or just plain wrong in my understanding of your posts, I know very little about you. You no doubt have a great deal to think about. Try to give yourself a break every now and then from all these questions. Patience will do you a world of good in all this.