ITFD and ED, it seems clear from your posts that you are not speaking from experience, but rather from surmise, assumption, and confirmation bias.
I understand. That’s how most of us approach things we don’t understand. We reach back to opinions and perspectives that are self confirming.
I can tell you with absolute certainty that children DO NOT benefit from a couple staying together when there is a poisonous relationship between the parents. And even when it is less than poisonous, but still negative, the children see and hear and learn from what goes on. If you think staying married “for the sake of the children” is justified once steps have been taken to repair the marriage without success, please don’t involve yourself in any marriage issues. You’ll do more harm than good.
As for the notion that an external individual can accurately define abuse in a marriage, the notion is strange. Clearly there are legal definitions of physical abuse, psychological definitions, financial definitions, but there is also coercion, blackmail, badmouthing the other, intimidation, deception, abusive language, passive aggressive language, and a myriad of other elements that can potentially constitute abuse, depending on the context. AND NONE OF YOU KNOW THE CONTEXT UNLESS YOU HAVE LIVED IN IT.
As I have written here before, divorce is awful. If it can be avoided, if a marriage can be repaired, steps should be taken and counsel sought be it through a Rav, a therapist or a family member to save it.
But when it can’t be saved, even two good but imperfect people need to learn what can be learned, change themselves if they can, as no one else, no one, can change them externally, and they need to rebuild their lives, for their own benefit, and for their children. What the people gazing over their hedge or talking about them in shul or when picking up kids from school think about it is irrelevant, uninformed and either malicious or fearful.
Are you gazing over hedges?