@tank121,
Hi Tank,
Firstly, I'm sad to hear of your situation - both for you and your wife.
Secondly, your wife is being deceptive with you about her affair, and about where you stand, and being so, she is also disrespecting you.
One of the most difficult things to understand in these sort of situations is that people always make the best decision they can for the circumstances they find themselves in. Your wife's decision might be a really bad decision, may hurt other people, and may have any number of other negative consequences, but that is immaterial to the fact it was the best decision she could make, for reasons she felt were valid.
That said - one of the biggest hurdles in the hurt you feel is usually 'how could she do this?'. So I would rephrase this and ask 'from her perspective, what valid reasons does your wife have for doing what she did, and what she's doing?'
You said that what she's doing goes against everything she's ever stood for, that she was always a stay at home mum, and that you were a workaholic, and 'shared' 4 kids, and had both her brother and her mother living with you...but now she's almost completely the opposite. What would drive a person do that? (by the way, there is usually not just one answer to this, but a combination of answers, including timeframe...small things can really build up over time in a persons mind)
You said that you had sex 5-6 times a week. Out of curiosity, was it always that way, or did it increase or decrease, and if so, when did the change occur?
What did your wife find interesting in life? What inspired her? What did the two of you do together to make your relationship grow? What does she hope for? What are her emotions needs? How does she hope (in normal circumstances) to have her emotional needs fulfilled? What makes her happy? What excites her senses (that may sound unfair, but everyone needs at least
some excitement in their lives - think about it.). What does she say she finds interesting, and what does she say she doesn't like?
How much time did you put into your relationship with her compared to other activities/people - remembering that you put the most time into the priorities in your life (going to sleep in the same bed doesn't count in this equation)?
Lastly, when you got married you were both in the same place. You've spent many years together. Have you both grown in the same direction? Has she become a different person to you? (that's a compatibility question. Love doesn't guarantee compatibility, or that you won't grow apart).
Hope it helps in some degree.