Some of the comments here and baiting of the OP are beyond ridiculous and not right. Some have just taken it too far and are not helping the OP make sense of the situation.
Some here are also just trying to add fuel to the fire suggesting that the guy had sex with the dancer, that it's a typical event that happy endings are a given. This is entirely in your imagination and certainly not in the norm and shame on some of you suggesting this to the OP to try and blow this into something worse than it is for her. It is not.
These licensed clubs would be shut down immediately if the dancers did anything more than a naked or semi naked strip.
I accept there are illegal brothels in the UK, massage parlours, prostitutes, escort sex workers etc that provide these services and if some sleezy bloke wants to seek that out that's an entirely different situation. There may even be low grade clubs that flaunt regulations like a poster here suggested as a dancer she offered more, but this is not a typical situation.
In the OPs specific case, her otherwise decent husband, had a lapse of judgement whilst off his face on a stag night. It doesn't make it right but it's NOT a hanging offence. He sat on his hands, a girl most likely student, did a two minute strip as his mates had bunged her a tenner or whatever and no touching lap dance and that was it. I am a guy and i can tell you for a fact this guy like many intoxicated guys in this situation probably wasn't even paying much attention. It's not private is it with loads of other guys and girls dancing around you and guys cheering others on. Further, one of the previous comments that he would be erect and excited about this and touching himself is just plain wrong. Now i can't say if he got excited or not, i wasn't there but there is a possibility he wasn't actually that interested in the dancer and wanted to return to his beer.
I appreciate some feminists here think all men are rabid dogs that will fck anything but sorry to disappoint but that is NOT the case for ALL guys.
Now, he has come clean to the OP and felt he could talk to her about it. He obviously considered he had the sort of relationship where he can talk to his wife. He didn't go off visiting prostitutes and then lie to his wife, no he has been open and honest about the stupidity of the situation, further her husband regrets it. The guy is unlikely to repeat the situation, if he did he would be toast. He will likely learn from it and not allow himself to be put in a stupid situation like this in the future.
I am speaking from experience, i made a similar dreadful mistake like the OPs husband years ok as i say. Incidentally, i don't keep in touch with some of the guys on that stag night but i learnt from it, matured and NEVER did anything so stupid again. I have been happy married now 24 years and never looked back. I wanted to reply to the OP because i had real experience of her situation i wanted to share from a different perspective, especially in view of some of the comments here. It is NOT worth breaking up an otherwise great marriage over this minor indiscretion.
Those posters here advocating she should leave her husband over this, well shame on you. There is a vast difference between this situation, a guy seeking out prostitutes or a guy having some secret affair behind his wife's back. As i say he has been honest and open with her, he's not done this behind her back and unlikley to repeat it
GOOD LUCK