I know when my wife was having her affair, someone on the SSM board (NOP) told me that, after the initial shock wears off, that the lies and the disrespect would be worse than the sex part to me. I doubted that would be true, but sure enough, nothing ended up making me angrier than when she'd look me dead in the eye and tell me where she was going, and then I'd catch her lying about it. Eventually, I had to have a separate confrontation with her about "NO MORE LIES." I told her she needed to come clean with her parents and with our adult daughters, and no more lying to me, because it was disrespectful to all of us, and besides, if their relationship was so wonderful, then why the need to hide it?
I'll never forget the meeting. We were sitting in her car in a department store parking lot, and I told her we could either drive to her parents house RIGHT THEN, and she could tell them the truth, or I was going to, that I respected them too much after everything they'd done for me to allow them to be lied to anymore, and the same for our daughters (20, 18).
She was LIVID, and bought like hell, but she came clean with all of them, and the affair ended soon after.