Gwen - many of us here have felt that - and very very occasionally I still do.
It is a result of abuse, including emotional abuse. 'It must be our fault' Please read up on emotional abuse - and I see much MLC behaviour as emotionally abusive because it belittles and hurts the partner.
If you read up on emotional abuse, I suspect you will find both some 'Aha' moments and some personal strategies that work for you.
