My take on it is first, of course you were hurt and angry because you were deceived about something that included "sex-ness" and your DH (fiance, at the time). That is perfectly understandable and of course you're not an idiot. After all, if it was no big deal then why did they all conspire to keep it from you, hmmm? Your husband, and the rest of the guys, and the other guys' partners, all knew it was an issue and that proves it, if there is any doubt (which there isn't).
But then there's also that whole other side of this. It is a longstanding, though icky tradition for a guy's buddies to drag him to a strip club at his bachelor's do, where shenanigans ensue, his last taste of singlehood, a rite of passing. We also know this, correct?
Imagine husband (fiance at the time), these are his buddies, they've arranged a big naughty thing, followed the ick but existing custom. This is not sex-sex, it's the wild fun of being naughty and stupid and drunk with your pals, the last hurrah. Imagine yourself in a similar position. Your nearest and dearest gal pals drag you to see male strippers. Once there, you're in the spotlight, everyone howling with laughter and cheering you on. What do you do? Go along with it or shut it down, putting your friends in their place when they were obviously trying to arrange a big naughty memorable last hurrah in your honor?
As for nobody else telling you, well obviously, the guilty friends do not want to touch this later with a ten-foot pole . And it's likely some, most or all of their partners didn't know, or were only told a cleaned-up version, or didn't think it was a big deal anyway. It's likely nobody knew what you knew or didn't know but wouldn't want to set themselves up for trouble by telling you. Listen, in the real world, nobody wants to be a snitch. After all, there can be huge repercussions for it.
I think he got caught on the spot and tried to maneuver it in the way he thought would be best, keeping in mind he was under tremendous peer pressure, publicly, without warning and likely half-drunk too. Of course he didn't want to take a big stand and be School Marm Super Dork in front of all his stupid friends. Then of course, he thought, oh shit. My girl will never, ever understand this. I better just. Be. Quiet. This is all quite juvenile and stupid of course, but I do not think it's even remotely comparable to him having an affair or anything like that.
In summary, if you follow and agree with my reasoning, I'd say yes, it's definitely quite understandable that you were upset and also yes, you should follow where his mind was at and the situation he was put into and forgive him. Now if he sneaks off to a strip club without your permission any other time, that's different.
I've always felt like these bachelor and bachelorette things were a very terrible idea in the first place because them leading to this kind of upset between the couple is very, very, very common. I got married decades ago when all this crap was even worse. What my husband and I did was announce that we didn't want any separate bachelor and bachelorette (or whatever they're called now) dos, we wanted a joint bachelor/bachelorette dinner instead, and that's what we had. I don't feel like people who are engaged are really still single, they've already made that commitment to each other, so why be set up for trouble in the first place? Sorry this is so long. I hope it's helpful to you. :)