Semeon,

I am not sure that you can learn much about this particular experience, specifically due to its highly peculiar nature. What are the chances you will have another relationship like this? They are pretty slim. I think the only one lesson you can effectively draw out of this experience is the one sophiesmom has suggested - STOP BLAMING YOURSELF.

There is this expression that it takes TWO to tango. You could not have possibly been responsible for blowing this all by yourself. Nobody is THAT powerful. There is a dynamic between people - you cannot control everything what happens within a couple.

There is an additional danger in blaming yourself (in addition to the low self-esteem) - you are in essence overestimating your abilities and power. It is the flip side of low self-esteem in a way. I hope this makes sense, and, please, do something relaxing and nice for yourself and just go with the flow and enjoy the moment - do not spend all your waking hours analyzing what happened over and over again.