Thanks for all the replies, it's good to know I'm understood.
It seems that he hates surprises. Since the affair anything a bit out of the ordinary, and I'm only talking about the odd massage or putting on the stockings, has to be pre arranged or at least pre hinted. I can't just do anything, apart from everyday sex, on the spur of the moment. Odd.
My h too was completely different with ow sexually and did the normal affair things with her, such as sexting, sex in the car etc, that would never come into our relationship because a) I would never take a photo of my bits, b) he would be too shy to do either of the above with me and c) I'd worry about getting caught! I can cope with all that and put that in the right compartment. However it is still something he experienced in our marriage without me and was more than willing to do.
What I get really upset about is how he talked to her about his fantasies, which he may have just made up on the spot but he still, apparently, engaged in this conversation and they carried them out. If I've ever asked him, even pre affair, to describe one he just laughs and says he doesn't have any. In other words makes no effort to play along.
Also it seems that whatever she wanted to do to him sexually he went along with. He says he didn't get a lot out of what they did and I do believe him, but again I with her he understood that doing what your partner wants is part of sex. (When I say he said he didn't get a lot out of it He meant it didn't move the earth for him more than anything else - of course he enjoyed it)
Don't get me wrong, our sex life has rebuilt itself quite we'll and he is an attentive lover but he just won't go the extra mile with me as he did with her.
From what I understand of their affair she was the dominant one in and out of the bedroom, although he played the dutiful puppy quite well. She was more sexually experienced than him, perhaps he was trying to prove otherwise? Or did there relationship have nothing but work and sex in common so had to improvise?
Secretly, I think she was just a better lover than me and he was more attracted to her. But then he'd have to have been more attracted to her to have the affair in the first place.