Women are usually harder to crack than men, because -- typically -- a woman will have emotionally checked out months, even more than a year or two ago by the time they cheat. They more often than not plan this stuff for month's on end, and by the time you get the bomb drop, they are DONE.
This goes directly to your finding out how much longer this had been going on than previously thought, CD. She's in DEEP. You're not going to break this thing -- if you are to break it -- with one glorious speech.