noodle

I recommend getting some help/input from someone you trust or a professional. Immediately. Suicidal gestures, statements, etc, are nothing to mess around with. You cannot control what he does, no matter how you try. The only thing you can do is to call someone if he tries to hurt himself. People who are desperate, especially during a breakup (or perceived one) tend to do and say things that they normally wouldn't, in my opinion. By letting him know, "This is what I'm choosing to do, it doesn't mean that I love you any less, but if I don't take care of myself, I'm no good to anything else," that you understand he will do whatever he feels is appropriate, and that you will respond with what it takes to keep him safe, you're establishing boundaries. I hate being the one to say, "If you continue this behavior, I'm leaving and I will call someone to keep you from hurting yourself." But I've done it twice with people I cared about. Once with good results (he got a wake-up call and didn't do anything, but sought out counseling when he saw I was truly concerned) and once with not-so-good (fury and "You bitch, I'm never speaking to you again, how could you threaten me like that?!"). Either way, they were both safe and I got what I needed... space to make my decisions and to breathe.
Please make sure that you're talking to someone who you can turn to in a time of crisis. A trusted friend or family member that is not going to put on the superhero outfit and try to save the day, but someone that will listen and that you can call when you leave his vicinity when he's acting like you described. We all need support.

Self-harming behaviors... from drinking to cutting to punching walls and making statements... are very serious. You are not the person to decide if he is serious or not. It's natural to be fearful when you care about someone, but there is a line between caring and protecting. Please, please get some help to empower you to do whatever you think is right. I'm a reformed mental health therapist and I've had more kids than I care to think about Baker Acted for serious suicidal thoughts or actions. But not one of them actually succeeded in killing themselves during or after I made the calls and as far as I know, they got the help they needed... more than even I could provide at the time.

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