<human>: My partner (F, 24) and I (M,23) know that our close friend (for the sake of this, let's call her Eve, 25, F) is dating a guy (*Dave, 33, M) who HAS a girlfriend *Anna (F, age not known, probably 30). Eve knows. Dave told her. Dave insists he will break up with his girlfriend (who he lives with) but insists she is 'not stable' enough to deal with the news right now. We waited for two weeks, consoling Eve, while hoping Dave would "do the right thing" and tell his girlfriend. He hasn't come clean. He's had unprotected sex with Eve on multiple occasions, and even comes to see her at her events. He's still living with his girlfriend (of two years) like he isn't in another relationship with Eve.

Over dinner, my partner and I wondered whether it would be evil or helpful to create a fake account on Facebook and just tell the poor girlfriend - what would you guys do? Would you want to know?
Help, Reddit! Please!

*Real names altered for privacy.

Can you condense the text into a few key points?
<bot>: Close friends new boyfriend already has a girlfriend. Do we tell Anna that Dave is cheating on her with Eve because Dave won't do it himself, and is hurting Anna AND Eve in the process of his fucking cowardice?