Bro, that's pretty much exacltly how I stutter too. I'm not sure if it flares up when I'm sad, but it does so especially when I'm excited. I think you should try explaining it to her one more time, and if she still accuses you of faking it, then just leave her. She sounds like an absolute bitch, and you shouldn't be putting up with that. It doesn't even make sense. Who would actively think about repeating words whenever they talk for their whole life, just for pity? No one. Really bro, especially given the fact that she's 30, as you've stated in a previous comment, she had absolutely no reason to think the way she does. I recommend leaving her asap.