I've been dating this girls for about 4 years now. She's a solid HB5, always cooks, cleans, down to have sex/give neck whenever I want. She's super mature, intelligent, I've never really met a girl like her (I know oneitits hahaha but nah). Anyways, everything has been really great, up until last weekend...

I found out she got with my friend about a year ago but it only happened once (just head) but honestly he's a beta male so I feel like it doesn't really count. I haven't brought it up to my LTR because I'm honestly not even that mad because he's a beta male so it doesn't really pose a threat to me. How would you guy's handle this? The guy is one of my best friends so I don't really wanna bring it up and make it awkward between us. I'm pretty confident that nothing else will happen because I know from a couple of his exes that he doesn't last very long anyways, should I just continue running amused mastery game instead of getting defensive to her and coming off as beta? Thanks