Thought she was cool at first tbh....

I swearrrrrr, like stfu you hypocrite

But that doesn't have anything to do with their relationship?

I get what you mean but she is calling him a traitor but she was seeing the married man and he wasn’t technically cheating on anyone so she shouldn’t be hypocritical (●'◡'●)ﾉ Hope that makes sense.....

Yeah, you just spelled out your original comment in more detail. And my reply stays the same: It doesn't have anything to do with their relationship. As friends. He already know how she is. They've been fine despite that. But making the choice to get together with her supposed lover makes it personal between them.
She's not spotless, but that's part of her character. They're probably going to make up with that somewhat in mind.

this isnt even about their relationship what are you even talking about. she, a home wrecker calling him a traitor is hypocritical. 1+1=2

Of course it's about their relationship. She giving him shit for this is because it's something that is between THEM.
If she'd had a problem with him just sleeping around with married men or women, than that'd would be hypocritical, and the end of it.

no see what he thought he was doing is “sleeping with someone else’s partner” and that is actually exactly what SHE IS doing and then her getting mad at him for THAT is hypocrisy..... i believe

Oh, undoubtedly, that's what he's been doing, but his actual dilemma has always been about him sleeping with his best friends' lover.
Don't get me wrong, Mari IS flawed. She's supposed to be, as a character. She may even be a hypocrite, but sending all this hate her way for feeling betrayed by her best friend, that's a little over the top.