And i think you are also making a statement that we all play a role. Like in bullying. It happens because there are many kids that stand back and just dont say anything. I think that the new anti bullying training tries to involve every one.
And yeah. The OM/OW is a big part of this and does have a responsibility. Sure it ultimately falls on the waywards choices. I have heard if it wasnt this person. It would just be someone else. But i think its a very clear' your in the wrong to go out with someone that is married and has a kid. Although a person with no relationship experience in their late teens early 20s really does not understand the gravity of this unless they witnessed it happening in their own family. When ineas in my late teens mone of my close friends was running around with a married man. She would tell me how evil his ex was. I stayed friends with her but told her shebwas crqzy to date this guy. She ended up stalking him and scaring him. And our friendship ended cause i realized she was a pretty bad person for other reasons too.
Your friend is 26. Does he have relationship experience? She is much older and knows how to manipulate a situation i am sure.