I agree with both Cogito and izzy.
I agree it might have been more tactful for DH not to tell tales on himself if he did something that he personally didn't find sufficiently objectionable to object to but thought it might cause you some anguish.
If you met someone you found rather attractive, flirted ever so slightly and found yourself subject to a small imagining that would probably hurt DH's feeling, would you go and blab to him about it? I would consider the experience to be entirely innocent, harmless and even fun (assuming you didn't take it too seriously!). However, you would seriously risk making it into something else by not keeping it to yourself.
Also, to reinforce izzy's point: although I'm sure you are a perfect wife and companion in every respect, stand out from the crowd, never suffer lapses of judgement, are strong minded in everything and never follow the herd, always consider and comply with DH's expectations of you in thought and deed, etc., you must be patient and accept that no husband has a chance of raising himself up to such a standard and so you must make some allowances for this. Just to hedge your bets that by some aberration you do slip up one day and cause him some offence, bearing in mind that it will his feelings about what you've done rather than yours that matter, it might be worth setting a precedent for tolerance and forgiveness.
I don't agree with the poster who says that shagging and visiting a strip club are the same things. I suspect you would be posting a very different set of question if DH had confessed to the former.
I come back to thinking the best thing to do is to figure out what you feel and why, without cloaking this in justifications, and then talk to him honestly about those feelings without threats or accusations. That is the most effective way of getting him to see your point of view and, maybe, even hearing his (which presumably, given you are perfect, you will want to do
). A marriage has to be based on honesty and trust but with a bit of fair, negotiated and respectful leeway to allow for the fact that we're human and, also, don't always see things the same way.