For those suggesting I share with him what I've shared here, as I did here, I did. I talked to him (hence why I've got lots of information on his points). At some point, unfortunately, after you've both listened to each other's perspectives fully, and still disagree though, it's not really "trouble communicating" or a lack of "an adult conversation." It's a disagreement over values/spending etc., not a lack of understanding, explanations or communications. (And there was no "permission required to go" either. Not sure where that came up by a poster. I was unhappy with his decisions and actions, but I did not say he couldn't go, and in fact explicitly said I wasn't going to do that although I admitted wanting to do so. I'm not perfect, I experience anger/envy/the other 7 deadly sins, etc. But heck, the whole world would be condemned if we went by inner thoughts/emotions rather than actually our actual actions and words.)
Update: We attended the (destination wedding) for the most recent bachelor party this weekend. A few things came out:
1. A number of the wives aren't happy about this spending and bachelor trips, to varying degrees.
One is incredibly unhappy in (her one year) marriage on a number of fronts, and finances is one of them. One significant difference is that they are apparently quite pressed financially and the husband's lopsided spending takes away not from savings (as in our case) but in the wife having any money to spend on things for herself. While we're getting a lopsided story that doesn't entirely add up, knowing this was sobering to my husband as he doesn't want his buddy to have these issues in his marriage, nor did he realize it was that bad.
I think knowing multiple wives feel this way (and it sounds like if things don't change with the one, it could end up in a divorce), may help the guys to moderate a bit more in the future, as before they believed it was "just their wife" but the others were "all cool" with it.
2. I recognize that maybe we really are at the end of these parties in this group
We looked around at the wedding and realized that at least in this particular college group, maybe everyone really is married off, almost all within the last five years (the guys are mid-30s). So there's less of a reason for the "bachelor party." Only a few have kids so far, but more want them, which will make trips harder. If I can genuinely believe this is the end of the "lifetime trips", and there aren't going to be yet more surprise trips next year or the following, then I can have a better grace about these. Part of the frustration is the feeling that each year the parties are a surprise and are anted up higher and higher each time.
3. The guys have agreed it might actually be fun to have a group trip with the wives too.
This is the first time the couples in this group really spent any length of time together, as we all spent a minimum of three nights at the resort for the wedding activities. (The guys are all in the same fraternity. I'm one of a few wives that attended the same college and knew most them back in the day, although not super close, and I didn't meet my husband until many years after graduation as we were different years.) So it helped to have everyone get to know each other better, have a good time, and realize, wow, it could be fun to do again. The wives also proposed that if they needed it, the guys could go off and do their own things during the day (as would we) and get together just in the evenings.
4. And separately, DH has said he actually doesn't want to do the upcoming bachelor trip (for an old coworker) in mid-August.
He's emailed out as Best Man, but is hoping the others can't make that particular weekend. He gets burnt out by travel, and between the parties, the weddings (had two this past week), and work travel, he has little juice left in the tank right now (which isn't much fun for me either). It helps me to know he's at least making an effort now to suggest other options to the groom rather than just going with the flow. It's not that I necessarily expected him to say "I won't go", I really just wanted him to just try to moderate the trip and propose fun activities that are more local and thus less costly for vacation and money.
Re the idea of this being an arms race, it's true in the case of this upcoming party. DH told me he thinks the groom mostly wants Vegas because he wants the bride to realize that he too could have strippers at his party, and that will influence her to moderate her behavior at her party. Seems a shitty reason for a party to me (and one ought to trust their partner), but what do I know?