I have to disagree with you Larry.
I don't think any door should be closed on a couples sexuality without discussing it. If he brings it up in the fashion that it has been discussed prior, it is not violating her 'privacy' or compromising it. By discussing it with each other, he is able to express his desire and she can share with him how she feels about allowing him to watch her. To not discuss it means that
'incommunicado' is having to stifle his desires and she is having to hide something in which she derives pleasure.
What is the worst thing she can say? "No, I'm not comfortable with that, because...." And even if she say's 'NO', who knows, maybe she will derive even more pleasure knowing that it is driving him wild whilst making for a more intense orgasm for her.
Win, Win situation, in my opinion.