It was my girlfriends birthday last weekend so she invited me and a few of her friends out for drinks. The night was going well, we'd gone to a few bars and then went to a club.
Her best friend has been in a relationship for around 3 years now. I've met her boyfriend a couple of times. When we got to the club she starts dancing with random guys and then tries to kiss one of them. The other friends moved her away before anything could happen and then she proceeded to do the same thing again shortly after.
I mentioned this to my gf and said her bf deserves to know but my girlfriend just said it was none of our business. I didn't really want ot leave it though as I'd want someone to tell me if the situation was reversed so I messaged the guy the next morning and told him what happened.
My girlfriend comes up to me and asks if I'd messaged him. I told her yeah and asked why. She said he told her friend that he knew what she'd been doing and that they had a massive argument and now they're over.
My girlfriend said I was to blame for their relationship ending but I just pointed out her friend only has herself to blame. My girlfriend just said I should have stayed out of it.
How would you handle this?
tl;dr my girlfriends best friend repeatedly tried to kiss random guys on a night out. I told her boyfriend what happened and they got into an argument and broke up. My girlfriend is blaming me for their breakup