MY – “Health – I am a kallah teacher, & it’s part of my job to impart a LOT of hashkafa, and eitzas on behavior in marriage. This is not something I originated – it was taught to me by my kallah teacher trainers, & is widespread among Kallah (& I assume Chosson) teachers.”
Well unless these trainers have had psychology training specifically about marriage/interpersonal relationships -they should not impart their wisdom on marriage. Leave it to the professionals. Eg. therapists, Rabbeyim and Morahs. And believe you me not all that I just mentioned are all qualified either.
Being taught something by s/o else -doesn’t make you qualified, unless they were qualified.