How do I tell my girlfriend I slept with her friend since we started dating?

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1 y
So I didn’t mean to post it before adding context,
My current girlfriend mentioned she slept with bigger guys before me an seems a bit of a size queen, I’m on the smaller/below average side an haven’t ever felt enough, she’s made comments about slipping out an not having a variety of positions available etc an her friend approached me when we were both drunk an she was asleep an we got into some action, she was very comforting about my size an it’s sorts been a regular thing since
Updates
1 y
Sort of feels like nobody sees any of my context, she made me feel shitty about something physical I couldn’t change but I still loved her a was faced with a dilemma? I didn’t do it to be horrible it was impulsive then addictive when she never showed any appreciation or compassion to me
How do I tell my girlfriend I slept with her friend since we started dating?
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