Time To Go
I can understand this person’s anger. It is hard to watch your parents be treated badly. We may not know all the details to this story but I think we know enough to know that this marriage must be a nightmare for the woman who has been cheated one and disrespected. Unfortunately, that is a situation that only she can fix.
Maybe someday your mom will get the strength to leave this person. You should never stop reminding her that she deserves so much better than she has been getting. She should give herself the chance to find happiness. Who wants to be miserable their entire life. Time passes too quickly to waste it on people who hurt you.