i agree with hk, you have nothing to be guilty about, i think all of this was manipulation at it finest, and its a sad thing, that puts you in a bad place cause you never know if he actually will suceed and now it puts you in a place where you are not allow to do anything that he disagree with or that doesn't cater to him. now you are afraid to take care of yourself, for fear of him killing himself. this puts you totally under his control, if you allow this to happen to you.
this is none of your fault. first, if he really meant to kill himself, why would he call you to tell you that he was gonna do it, unless he wanted you to be his savior. how far did you say that you were away?
i thik that you did a good thing, you call the police, so as to get him so help. personally i probably would have done what you did and would do it again the next time. if it worked this time and he knows that you feel so responsible, it just may very well be a next time. he may think that he can control your every move with sucide threats, this makes for a very uncomfortable situation for you. you are not responsible for his actions at all. sorry, but i think that your bf wants to controll you and you are not obligated to be controlled by his actions. you did the right thing, and i pray that if there is a next time, for which i hope not, that you would do the same thing in a heart beat. this has nothing to do with you and its not your fautl, please don't take the blame for this. love ya