You can't stay with someone because you're worried about their response to your breaking it off. But, just so you know, I was physically ill at the thought of ending it with my aexbf before I did: It was awful. I knew it would devastate him and I really didn't want to hurt him, but knew I had to do it so I did. It was every bit as nasty as I expected, and I am totally glad I did it anyway. I think it's the first self respecting, non-cowardly thing I did in that relationship in years.
One other thing: My SO was away when I broke up with him. He was also scheduled to return back to our home at the time I did it. I broke up with him over the phone after a 9 year relationship because the idea of having him come home expecting some great re-union while I was planning our breakup was just to uncomfortable. Also, the distance minimized the opportunities for his creating drama. Finally, I had made the choice to end it, and didn't want to mislead him for the time between when I decided and when he returned home. I don't know if any of these reasons "ring true" in your case, but that was my thinking on it.