They are causing their former wife or husband to be adulterous.
Plus they are being adulterous — they are already married to wife or husband 1.
Solutions: Work on your first marriage.
Pursue and annulment.
I don’t understand how your comments follow from mine but my wife (who was previously married and divorced to escape with her life - only slight exaggeration) and I are chaste and not adulterous. I was not previously married.
Oops,
Pursue an annulment.
Huh? No one can cause another to be "adulterous" without that person's consent.