I think it does not matter under which circumstances people are married, and it also does not matter who they are been before or after marriage, because GOD created woman for man and they shall become one flesh joined together in marriage, which was made long before any Law came to existence.
So this means that the Law of marriage is UNIVERSAL and applies to whole humankind without any exception, because it is a Covenant not only between man and a woman but also between GOD and humankind.
So breaking the marriage means breaking not only Covenant of Marriage between man and a woman, but also GOD’S Covenant of Marriage.
So all people, no matter who they are, religious or not, would bare their own consequences for violating the Covenant of Marriage while are both parties still alive.