I don't know what ive done?

When i was 14 i went out with a boy from my scout group we were real close and after a month decided it was best to be friends as we were really close, he went out with a few girls then a year later after we had dated, stuff happend like we kissed randomly, even after that we remained close, he left scouts and had a gf hu was real obsessive and we lost touch only speaking every now and then on msn, after a while we completely lost touch. i recently found him on facebook, sent him a msg and added him but he completely blocked me, i know this coz i checked from my bf's where i can locate his profile, the thing is i dont know what ive done??