<human>: When my ex and I were actually dating, we were 17/18. Since then, we have been talking very little, obviously, but once in a while we still hang out and have a completely platonic but intimate relationship. I was a jerk to her when we were dating and kind of ended things abruptly. But years afterwards, we've talked about it and in terms of emotions and our relationship to each other, I'd say we've achieved full closure.

But the twist is this: back when we were dating, I cheated on her with a friend of mine. Now, I've never been one to confront my problems, so I am very tempted to never bring it up. But I am only human and can't stop feeling guilty. I've apologized for being a shitty boyfriend but I've never mentioned this detail. She's the sweetest person in the world.

(To be clear, we've both moved on and have absolutely no feelings for each other. Apart from this thing—so, from her perspective—we have complete closure.)

Can you give me a shortened version of the text?
<bot>: I never told my ex that I cheated on her. Telling her would make me feel better; but better enough to justify opening this can of worms after so long?