Yes it's normal to fantasize about having an affair. I'm in a healthy sexual relationship and I still fantasize about being with other men. Now, there may be some emotional needs that aren't being fulfilled . . . But thems the breaks when it comes to monogamy.

What's not normal is how your wife refuses to seek help or explore her own sexuality. I'm not attacking her, I'm merely stating that she is removed from herself, and this is not normal. It's not healthy for your relationship, and it will begin to cause strife. It sounds like it already has.

It doesn't sound like she is just someone who doesn't like sex, who is non-sexual. It sounds like she has a neurotic aversion towards it. I can almost guarantee your wife probably gets the dirtiest flashes of fantasies going through her mind at times, and she probably feels insanely guilty for it.

Seeing as though her attitude seems to be that only "dirty girls" orgasm, I wonder if she would benefit from being treated like one? Maybe she needs to be put in that mindset in order to orgasm? I realize this may be kinky and extreme to some (it's barely anything to me), but it might actually work. She might benefit from being treated like a dirty girl. Maybe that's what she wants.

I'm not saying to break out a whip and start humiliating her, but maybe you could try something different, like blindfolding her or tying her wrists together. She needs the control taken away from her. She might need some more force.

Or maybe you should talk to her during it. Ask her what she's feeling. Ask if she feels good. Tell her it's okay to let go. Tell her to orgasm for you. Keep telling her. Don't give up.

This is just a thought. I could be totally wrong.