You remain under the law of marriage if he's alive (Rom. 7:2, 3).I really don't expect any better, especially from the guy with the grudge. The fact is ... I walked the walk ... which means that even though my ex-husband cheated on me (while I was pregnant and taking care of our infant son), I did not do the same. Even when the paperwork was filed and my divorce was pending, on the occasions I was asked out, my response was "Though I am going through a divorce, I am STILL a married woman".
See:
Divorce & Re marriage: A Position Paper by John Piper