A very intriguing topic indeed!
Red flags in a person!!!
Well, sometimes this person is really in a very closed environment and sometimes it's really inevitable to avoid this person.
You have talked about a "spouse" situation. That too, if the person has no kids - can come out of such toxic relationship (considering our society: where a mother can't survive without the said support of a husband - however toxic the relationship maybe).
Anyways what about those people who you can't escape? Who are somehow an integral part of your life - whether or not you want them to be...
And you are just unable to avoid these people and situations at any cost.
Recently, I watched an American season "shameless". I stopped watching after season 2 (due to the x rating and the ethical values twisted to almost ugliness). However it revolves around a narcissistic father (too many red flags) and a bipolar mother (drug addict, narcissist and whatnot).
The fate of such kids is always doomed.
Its a very grim topic but times are changing, many are getting out of toxic relationships even with kids and what we can do is support their choices.
Those people are the ones who are unhappy with their own lives as far as i think. Don’t let them and their actions bother you they are just unhappy people. You do what’s best for you and put them on ignore mode ;-)