The following statement is regarding naskh (abrogation):

"The existence of abrogation within Islamic legislation is among the manifestations of human welfare considerations in Islamic legislation. God may prescribe a law suitable to people at the time of its enactment, or it may serve a particular limited purpose."

Today a lot of reverts have spouses who are non-Muslims, yet are supportive of them thereby making it difficult to divorce their husbands and breaking up the family.

Could the previous law of allowing Muslim women to stay with their non-Muslim husbands be re-enacted in this case? In general, if the reasons for the previous law re-occur, can the abrogated law be re-enacted?

The One who made and makes laws does what He wants and when He wants, and every time there is hikmah in everything He does. Naskh is from Allah and after the death of the Prophet (ﷺ), naskh stopped.[1]

The ruling which was made about the wives and their non-Muslim husbands still applies now as it applied then.[2] So, the ruling is that the Muslim woman cannot be with a non-Muslim man. He is not her equivalent and she is not his. She is way more superior to him.

Having said the above, I think it is really difficult for the sisters to leave their husbands and sometimes the issue of the kids comes into play which makes things more difficult. The hukm itself is clear, but dealing with the situation is very difficult.

One of the Sheikhs in Medina once said that we have to try to look at the situation the lady is in; if she can leave the husband and carry on with her life without much hassle then it's best for her to leave immediately. On the other hand, if she cannot simply leave as that will affect her, then she should make the intention to leave, make the plans to leave and then leave when she can, and in the meantime while she is with her husband she should give him da'wah.

Getting back to the initial question, I will say that after the death of Prophet Muhammad (ﷺ), since there is no more naskh, even if the reason for the previous law re-occurs, the law at the time of Prophet Muhammad’s (ﷺ) death remains. I don’t see how the reason will re-occur though because the Laws are from Allah and He knew and knows about what will happen. But if we say it may re-occur, then the state of the people and their nature will be enough to make us cope with it. As Allah says:

لَا يُكَلِّفُ اللَّهُ نَفْسًا إِلَّا وُسْعَهَا

"Allah burdens not a person beyond his scope...."[3]

References:

[1]  Sh. Najm Deen At-Tufiy, Sharh Mukhtasar Rawda, 2/252 – 273

[2] Tafseer Ibn Khatir, 5/83

[3] Surah Al Baqarah, 2:286