You most certainly can live without him. After all, you did until you met him.
And you will not die if he breaks up with you again. But I imagine you'll feel pretty lousy -- anyone would on this kind of a roller coaster.
The thing is, whether or not you keep subjecting yourself to this is totally up to you. It sounds to me like a whole lot of your feelings -- both of you -- are propelled by the drama of all of this. That isn't a putdown, it's a simple reality, and something that a lot of folks get caught up in, and after a while, they can't separate what feelings are genuine, and what feelings are a desparation made out of being tossed all over the place.
Here's the thing: when you say you want to be with him forever, might you consider that if how things are right now is how things will always go? You want THAT forever? I sincerely doubt it.
Why do you want to be with this person, really? Because of what he says to you? because of what you idealize things to be? Because in all honesty the age of this relationship -- not your age, the age of the relationship -- is in it's infancy. The depth of love you're describing really isn't the kind of thing someone can develop in a few months outside of fiction. It just isn't. I know it can FEEL that big, but it can't be yet, because that sort of depth takes time and trust to develop, and it doesn't happen on the kind of roller coaster you're describing, sweetheart.
I'd suggest you really look at the realy of this situation and understand that the chances are high that what's going on isn't an interruption to your relationship, it IS the relationship you have, and it isn't going to change unless you just let go of it and move on so that someday, you can have a healthy, sane and balanced relationship where real love and intimacy can actually flourish.
Because this ain't it, babe.
Editor and Founder, Scarleteen
My epitaph should read: "She worked herself into this ground."
-- Kay Bailey Hutchinson