You shouldn't fight for anything that has the ability and capacity to decide on their own volition.
Who are the objects of my reference?... Nigerian ladies of course.
One of the things that can make you a slowpoke or render you inferior is you trying to get what has already left you after they've pondered already.
Your girlfriend had sex with your friend,you were aware of it..you found out if it wasn't a rape ,later you discovered it was quite consensual...then why do you have to fight your friend, although you have to keep distance but why don't you deal with the lady by turning her into a real slut..yes there are ways in which that can be done.
Destroy her ,pretend to show her more love but kill her ...impregnate her then abort it,let her womb be destroyed, then she will realise the gravity of what she did.
my humble and stainless advice.

Very evil and wicked. Very wrong move. Whoever does such is evil and destroying themselves big time. 2 wrongs dont make a right

The revenge is not worth it no matter do, instead let her be because no mttr the level of punishment placed on any cheating girlfriend, will it reverse something that has been bleeped to unfucked mode? No i guess.

You're preaching treachery, why

obviously something is paining you. you need deliverance

Nicca is advising himself. Pelé, no be the girl fault say you be simp.

Na HIV or other STIs/STDs you go carry in the process of executing your so called revenge.

Oga you must have learnt your lessons, use it well.

That would be quite a wicked thing to do.
I believe if you won't destroy your friend for betraying your trust, you shouldn't destroy her for doing the same.
If you simply can't forgive her, just let her go

I sense deep hatred from a dead conscience...

These acts have succeeded in branding men bad.