The Other Woman

My husband had an affair 5 years into our marriage, so that would be about 6 years ago now.  Today, I saw her for the first time since finding out about it 5 years ago.  I always imagined what I'd do if I ever saw her.  Scream at her, hit her, let everyone who was within earshot know that she was a homewrecker.  I did none of those things.  I was with a friend that doesn't know about the affair and I'd like to keep it that way.  She was with her husband and children.  I didn't realize at first that it was her until I recognized her husband.  It was all so surreal.  We were passing each other and I wanted to turn around to look at her from behind, but I didn't know if she had recognized me and would have been turning around at the same time which would have been awkward.  I finally did turn around and she was not looking at me, so I don't think she noticed me.  My next thought was do I tell my husband?  Hey, guess who I saw today!  What purpose would that serve?