If a woman is cheating should she be confronted while she is with the other man or when she is at home?

I don't think you should confront her when she is with the man - I think you should confront her when she is at home and there is privacy and calmness. If you confront her when she is with him, emotions could highly escalate and cause something bad to happen.

She's a big girl and knows she has control over her cheating so don't bother to bring the male counter-part into the matter. Confront her on home turf. If this is not your mate, but a friend I would keep right out of it. If it means destroying your friendship with her then please do so. She knows what she is doing is wrong. If you are the mate then leave!

If you confront them together they cannot deny it.