Why don't you phone your firm's benefits company and ask if you're covered for personal therapy sessions. Seeing a councellor will help you to come to terms with your guilt and aid you in getting your mind off the whore that helped you to travel on this destination to your own personal hell you're now in.
People can handle monogamy but very few can handle celebacy for any length of time, particularily when temptation is there offering you a bite of the apple. That goes for both men and women, the cheater and the enabler. That is why it is very important to refrain from doing date like activities with members of the opposite sex when you are going to be away from the one you promised monogamy to. Too late now but keep that in mind for the future because you've already done it once so the next time will be a fight in your own head to stay away from Miss blowjob. It's like any thing that releases those pleasure chemicals (smoking, drugs, drinking, sex) In order to win the fight in your head to stay off of the pull of the chemical release you need to go cold turkey and stay completely away from the pleasure of your choice.
I don't recommend you tell you wife. If this was a one off blow job ("intercourse was never on the table" to that I say blow your justification out your ass because what you did is just as bad as any vag/penis penetration) then I think you'd just be cruel and trying to unburden your own guilt by telling her. Others will likely tell you differently but thats my take on you being a coward a second time by telling and just trying to unburden yourself.
Call your benefits provider and see if you can get set up for some professional guidance on this one.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion