The Mosaic Law allowed divorce without qualification, as long as the rejected wife was left with a decent legal status. Jesus said this was allowed “because of the hardness of your hearts,” and set another standard.
I think it’s important to remember that the key issue in most cases is not, “I need to get away from the horrible situation with Spouse A,” but “I want to have sex with Spouse B.”
No reasonable interpretation of Scripture mandates continued cohabitation with a spouse who is violent or otherwise seriously harmful. The complications arise when a person pro-forma married wants sex with someone other than the spouse. Then you get into the sifting of details regarding whether Marriage A was a “real” marriage or not.
Separation from sin and abuse, yes; divorce, no.