<human>: We had our first big disagreement over something silly and partly due to a miscommunication on google hangouts.

In summary, I told him in confidence that I thought one of his female friends/ex girlfriend had low self esteem because of some stuff she did in her past, which is irrelevant now. After our disagreement, he went over to said ex's house and told her exactly what I said to "vent."

Maybe I'm overreacting, but what he did feels so wrong.  And he shared stuff that makes me look like an a-hole, to boot! Now I feel like an idiot and can't stand the thought of having to show my face around her again. She is a very nice woman, and I have no problems with my SOs' friendship with her. I just don't understand why he felt the need to share that particular detail while he was venting.

We talked about it and he denies trying to make me look bad. Then he told me he will continue to vent to this girl because they are close friends.

Could you distill the essence of the text into 1-3 sentences?
<bot>: SO shared negative comments I made about an ex with said ex after an argument between myself and SO. Am I right to feel violated?