Few weeks ago some anon posted about watching a couple play Hundred Line and how after the prologue the girlfriend killed Eito without hesitation, so that means being in a relationship cures you from being into freaks.
I found their channel.
She is really into Yugamu.
So being in a relationship doesn't cure you from liking freaks, it cures you from liking evil freaks like Eito. It doesn't cure from liking kind and loving freaks (Yugamu).