Woah...

He didnt' write a no contact letter and both of you sign naems at bottom and send to her?

He didn't make his superiors at work aware of hte affair either?

He's playing for sure then...

He needs to write her a no contact letter saying the affair is OVER and both of you put names at bottom so the letter is written as a COUPLE

That is like first order of business after an affair is ended...