Wedding dilemma - I don’t support the relationship or them getting married but I don’t want to isolate my friend, should I go?

[Anonymous]

So my friend was dating a guy and found he had a wife at home. She confronted him and he then admitted it but said it was a “open marriage”. We (the friends) didn’t believe him and told her to speak to the wife to prove it. She later spoke to the wife on the phone who said it was an open marriage and that she was okay with it. A few months later my friend finds out his wife had no idea about any of this and basically he faked being his own wife just so my friend would sleep with him. His wife then filed for divorce and suddenly he proposed to my friend.
Of course we tried talking her out of it, but she’s got her blinders on and now they’re getting married. Her family have also given their blessing but they are completely unaware about any of this. Personally, I don’t trust him at all as he has lied and manipulated so I don’t want to go to the wedding because I don’t support it. Equally though i also don’t want to leave my friend on her own on her wedding day. What should I do?

[ArtemisSilver]

Part of being a friend is knowing when to speak up and break things off if someone goes to far.