if i was in your situation i would be upset as well. as a general rule i wouldn't be bothered if my boyfriend paid to have a stripper dance for him because i'm comfortable in my relationship with him and i know that he looks at them the same way i do; they are a cheap thrill. i know that if he was in that situation, he wouldn't shag her because he knows he's got a better, classier deal at home., as i'm sure your man does. however, the issue you have here is not so much with stripper but with the physical contact you and him are lacking.
men go to strippers because what they're doing feels naughty and they love not knowing the strippers name etc, and you cant blame them for that after being in a long term relationship. i think you should put this event to the back of your mind.
strippers aren't threatening, only real affairs are!
but you do need a reason for the lack of physical contact in your relationship with him, have you asked him for a straight answer? have you tried anything new for him? possibly wearing some nice new lingerie, tying him up or even doing a lapdance yourself?!