I highly disagree with Nana, believing in someone does not put a bind into someone else, nor does that make you selfish, believing in someone is to turst their judgement, that no matter what happens they will do whatever they deem appropriate for the situation I'd even go as far as to say that it is more o a selfLESS behavior as you put the judgement of someone else in front of whatever emotions you may feel about the outcome of it(while still acknowlleging your feelings toward the situation), instead of this what she preeches is a "fuck it we ball" mentality where no matter what you partner does you will be there for them completely throwing away any sense of agency from yourself when it comes to feelings for their actions which altho also selfless is toxic as you start to simpply ignore your emotions.
With that said Nana is NOT in a relashionship with Mizuki so I'd say that she is overall "in the right" for not interefering with what Mizuki does, they do not have any agreements of fidelity to one another or anything, so keeping her feelings of jelousy to herself in this situation is 100% correct coming from her.
