Good Lord. This smacks of lack of experience on the subject! I admit the first time I was present my wife was acutely embarassed by my presence, and it probably only happened because her bull definitely wanted it to happen in fron of me at least once.
It seems to me that most women are thrilled to be fucked in front of their husband and many glory in such a situation.
While I think some women might be uncertain how their husband is going to react, and might be uncertain of their husband witnessing his 'nice' wife submitting to kinky sexual demands most women definitely seem to get an added thrill, whatever the reason, when their husband is present.
A friend once told me being fucked for the very first time by a black man in front of her husband and the African's friends had given her a lot of tensions, concerns and fears. Then she looked over and saw that her husband had been pushed to his knees and was sucking one of the watching African men and all her emotional reserve was swept away and it was the moment she 'truly give herself' heart and soul to the African fucking her