If your wife is not meeting your needs because she is unwilling or lacking interest, or if she has physical restrictions that get in the way, then a conversation should be had about getting you looked after.
I believe that, us men, if we are not sexually active we start to lose interest in life, weaken, stop exercising and age fast. You don't want that, you need to keep the juices moving through and constant masturbation is a lonely substitute.
I'd also say if your wife is willing to engage sexually then you should never, ever deny her, especially for the reason that you were banging a pro that day, or plan to the next day. Never deny your wife.
If there is not a lot going on at home, then stepping out with a professional is the way to go. You will not get emotionally involved, you will not leave for her and you will not embarrass you wife with people finding out.
All this is assuming you want to stay with your wife because you are compatible in all the other ways.