Admitting to Something You Didn't Do

Kristelle • Hakuna Matata
So in the beginning of my relationship, I was at my boyfriend's house and I randomly started crying and I don't remember why I cried. He assumes it's because I cheated. Which I know I never did. It's to the point where I am about to admit to it, just to end this stupid argument. 
What would you guys do? Have you ever cried out of nowhere and didn't really have a reason why? Would you ever admit to something you didn't do just to kill it?