I identify with so much that has been said already on this thread.
We are five months down the road from my discovery of his emotional affair with a work colleague. I stumbled upon the emails and confronted him.
It turns out that he had put a stop to it already and he seems to think that this makes a difference.
He is sorry and beating himself up and will never do it again, so he says.
He is struggling to understand that I don't care that he's sorry or that he's cut off all contact and changed jobs, or that he'll never do it again.
I care that he did it in the first place.
That he took a twenty year relationship and a seventeen year marriage and bollocksed it all up because some other woman flattered his ego.
Whilst I'm at home, looking after our children and scrimping and saving.
We're still together for now.
We have vast debts that won't be paid off for another 4 years, and I have no income, so I'm stuck, frankly.
But every day I struggle to compose myself in front of the children and pretend to everyone else that it's all ok.
No one else knows. I have no friends in RL and I'm too humiliated to confide in my family.
Family events are the worst, with everyone assuming we're fine and them laughing and joking with him.
He's fun-loving, sociable and friendly; a devoted father who adores his wife, see.
Everyone loves him. 
My Dad would smash his fucking face in if he knew.