This was my exact question. Sounds like OP wants to argue for the sake of arguing IMO

if I had to guess I think the fml is just poorly worded. I think she means he'll drop the subject when he's wrong but when she's wrong he goes the extra mile making sure she knows it? I don't see how this can be am fml any other way.

I think it's definitely more that he wont drop the subject if he's right, but she and he will if she's right. As if he wants to rub it in her face and be prideful rather than just being nice about it. Don't know why I'm being downvoted? The other option is that only she argues when she's wrong, but she states HE argues with her. I've met people who will take it that they're wrong, but when they're right they run it in your face. I really can't tell what OP is trying to say. Needs to be worded better.

And he's stuck with someone who argues even when they know they're wrong.

Maybe this Jr high person was special enough to be worth stuck for