Of COURSE you didn't cause him to go mad! If anyone did, HE did, trying to handle 2 women at the same time! What in the world is the matter with this guy? How did he think he could get away with this?
Something tells me he has had some serious problems all along -- it's just maybe you didn't see them at the time. Maybe they weren't as serious previously, and are now just beginning to really effect him. But something is really wrong with him. I pity the woman he's going to marry -- IF he does.
I'm sorry he wasted so much of your time -- I know you cared for him. I know you thought you had a future with him. I just wish the symptoms had become apparent earlier for your sake.
Find a great guy who will treat you the way you deserve to be treated -- with respect and honesty! God bless my friend and please take care of yourself. Hugs, Lee