I confronted the OM during my W's affair on two occasions. When he dumped my W, changed all of his numbers and got a new GF, my W flew to see him. I rang OM's GF to warn her and OM himself.
No regrets. My W was furious but then, if she were proud of what she did she would have shouted it from the rooftops.
Expose.
You will not make the situation any worse by doing this.
Do not fear your wife's anger!
Me: 46 W: 46 T: 23 M: 20 DS12 DD11 DS5
W left: 01/28/08 Discovered OM: 02/26/08 W back for 9 days: 04/08 W returned 05/21/08 EA/PA - 01/08-07/09 W's MLC 2008-2014 (realised this much later)