I can relate to DefeatedDad when he says he feels like sometimes he's looking down at his wife through the OM's eyes. I've found myself doing that too. It's hard because when we do that, we are subconsiously training ourselves to place the other person into any intimate situation we have with our partner.
I know I need to stop it, but not so easy to do.
It sounds like you have insecurities about yourself, when it comes to sex with your WH now. And it's no wonder! Given what they've done. The reality is though, it had nothing to do with how we were in bed. Nor how we look.
I learned to get past the insecurities by turning things around. Why in the hell do us B's think we aren't good enough??? And why are WE the one's insecure now? What you have to realize is YOU are the best your WH will ever have. Just by not having lowered yourself to status of "Whore", like the OW did, makes you far more desireable. And as far as how you perform...ummm, lose yourself in the act, and make him worry if he's pleasing YOU enough. He needs to be one with the concern now.
Your WH should be worried about how he's satisfying you. Not the other way around. I remember a few times my WBF said to me, after I couldn't get in the mood and ended up crying... he said how I was who he wanted, who he desired... and then he hit idiot status when he said he knew I wish I could be more like the one's in his past, younger, ect, but that I was perfect the way I am... I almost choked on his stupidity. Kinda wanted to hit him. I made damn sure he knew... I love who I am. I love my body. I love sex. And my insecurities and lack of sexual drive have to do with how I feel about his actions and him, NOT about how I feel about me and sex. If I was with a new man, I'd probably be all about it, and this bag of shit would be gone.
You asked for some advice . I'd start by turning things around. Have sex for YOU. Don't think for a second about what he's feeling during it. Don't think about how you look and don't think about if you're doing it better than the OW. You know your WH sexually, far better. Trust me on this one. And when it comes to inhibitions, let them go. All you should be doing is getting lost in feeling it for you.