Shouldn't the third-person be thanked instead?

It’s very often for me to see that people hate or wanting to hurt the third person who is having relationship with their SO. As if they’ve forgotten that it takes two to tango, they ignore the fact that this situation actually an eye-opening event and benefits themselves despite having been betrayed.

Common example: A has been betrayed by B, B is having relationship with C. Upon finding out about this A lashes out on C, calling C husband stealer and want to make her regret her actions. A then goes back to B to ask why B did this to her and at the same time self-blaming herself. The acts done by A here clearly shows that A is a weak and clingy woman.

How it should be: Upon the revelation that B is cheating on A, A meets C while she’s with B to congratulate them both. A sincerely thanks C because she has shown that her husband is actually a cheater all this time and that she’s happy to have finally been shown the truth. As for B, A said that she only regrets one thing, that is, if only B did this sooner she wouldn’t have wasted her time with a liar (B) this long and could have spent (intimate) time with someone else. A acts indifferent toward B’s betrayal. A knows that C is not obliged to not having relationship with a married person, that other women other than C could have easily done the same thing so it’s wrong to scapegoat C, and that it wasn’t C’s fault because if B really was a loyal husband he himself, as an adult and married man, could have refused having a relationship with C. Without being sarcastic, A sincerely congratulates the relationshio between B and C. This shows that even without B, A is still a happy and complete person.

I am giving this example because I found that many people were stupidly acting like the common example I provided above, while they could have been smart and awared about their happiness in their own independence.