I don't have the WT library on this computer but there was a series of articles about this in the early 1990's. If there is spiritual endangerment, ie: apostasy by your mate... You may separate and divorce, its up to you. It would not be recognized by the congregation as a scriptural divorce so one would not be free to remarry. No congregational restrictions would apply to the endangered mate. The same goes for extreme physical endangerment or failure to provide financially for the family if its the man.
My brother and his wife divorced and neither was disfellowshipped. They lived separately until my brother married someone else 5 or so years later and he was therefore an adulterer though divorced by the state.
Did you know if you are unscripturally divorced by law, you are still considered scripturally married by the congregation. When you sleep with your ex wife without remarrying her you have committed adultery. Relations before a divorce is final indicate acceptance of repentance by the harmed one .
If an unscriptural divorce, the congregation views you still married in God's eyes but unmarried by Ceasar's law so any relations would be seen as fornication.That one blew my mind. What a clown town.