Anger is common since it is happening with my wife as well. The anger is likley to protect them from whatever pain they are in. Being in conflict like that can be terribly stressful. I don't sympathise overmuch since they brought it on themselves.
But don't take the anger personally, they are just really at odds with themselves and their life.
Shirley Paige suggested that when people are having affairs there is a fantasy-reality dichotomy taking place, where the affair victim presents everything the unfaithful spouse despises about their life, while their other person is a dreamlike fantasy to them.
Our spouses see us as everything in their life they have to get away from, and they are deluded into thinking that their affairs are the solution.
I know it doesn't help, but it does help you realise what the anger is all about, spouses in affairs feel trapped and the affair is an escape, much like drinking or gambling, etc.
Each time they see you, the trap comes to the forefront and they get angry because they feel cornered.
Don't think they are angry at you, its the life that they feel is inadequate that they despise, and unfortunatley, they make us the housekeeper of this unpleasant world they want to break free of.
Anger is common, and the more you pressure them, the worse it gets.
I call them on lies too, I hate being lied to.
The thing that bugs me most is my wife does nice things with me to ease HER GUILT. She will clean the house, or make dinner, etc, not to be nice to me, but to help her feel better about her having her affair and feel like she's paying her dues or some sick thing like that.
Its really annoying becuase of this trick of hers i can't gauge where she's at on any given sunday. :P
Is she feeling warmer towards me, or is she plotting another visit and feels bad? I never can tell...grrrrrrr