I agree that talking to someone ELSE might be helpful when you realize you're gonna blow up. Trying not to let it get to that point is the optimum solution...talking to her when you start to feel tense might be helpful....but mostly, don't second guess what you should be doing based on her. Communication is all important here, not only to reasure you but to reasure her, you're not going to relentlessly distrust her for something she'd never done.

Take care...