I was in exactly the same position as you and I was pissed about it too. That's why somtimes I think that Theo should tell OM's W about the A but then I can also see that that does not perhaps benefit Theo and I don't know OM's W or have any loyalty to her, whereas I would hate to see it make things worse for Theo.
Not all people do want to know either - it is just such a personal thing. If OW's H had contacted me then OW would have certainly had me turn up at my H's Co and make sure they all knew exactly what I thought.
I know of someone in our town who when she found out her H was having an A with another W she took her kids to where the OW worked, (in a hair salon), and she went in and said in a loud voice "If you want my H you can have my kids aswell" and then she turned and walked out. I could never do that to my kids but I bet for a split second that felt great!!! Saffie
Saffie me 46 H 46 M in 1986 D20,D18,S16,D13 H's A 01/05 to 07/06 H recommitted to M 07/06 renewed vows 09/06 Going from strength to strength