Like you I wished both my parents died good to keep the illusion high they were great and loving. Most parents struggle through life and wanted or not the child is rarely what they expected.
Dad runs out, mom is stuck and pointed at being incomplete and raising the next drug addict or kid in the gutter.
What is left if you work your arses off, yourself to death? Not depending on a man but a bit of appreciation, knowing that you are liked and this said by an adult instead of a child who doesn't know better as "loving his parent".
The other option is staying single and slowly being wiped out by life.

In the case of many like your mom they are cheated and abused with the end result even the children hate them.
Should moms stay? I tend to say no. If a man can disappear and doesn't care why should the woman? At least if she leaves there's no need to try to build a normal family and stay lonely for the rest of her life which sounds better than be hated and blamed for trying to fit in.

Isn't it interesting how these men are rarely blamed for scamming and abusive behaviour?

Greetings from a single mom.