A few reasons, Allen. One is the "I wouldn't attend a summit unless I was assured of its outcome in advance" thing, yes. People that SAY they are going to be supportive of your marriage aren't always so, and I found "blood is thicker than water" to be usually true, on average.
A second reason would be that it can come across as sounding forced, contrived, orchestrated (by you) to get YOUR desired outcome. When it's sincerely initiated by someone who just loves you, and wants what's best for you, and who's PISSED that you're being cheated on, I think it's much more effective. If everyone goes to the cheating spouse, using the same words and phrases, it's going to be like a politician getting the same blocs of text in e-mails to her office, versus heartfelt phone calls from angry/concerned constituents.
A third reason would be that I wouldn't want these intermediaries THEMSELVES to feel used or manipulated in any way. If I can say to someone (like I did to my daughter) who asks "Give me his phone number, I'll call him AND TELL HIM WHAT i THINK OF HIM!", and I can reply "Look, honey, I appreciate that. You do what you feel you need to do, I'm certainly not asking you to do that," then -- later on -- she will see that I allowed her to make her own decisions on the subject.
There may be one or two other reasons, but those are the main ones. I do think it's best, that if you ARE going to ask for support, to keep it general and say "anything that you might be able to do to support our marriage, and bring some pressure on (Wife) to hopefully end this destructive behavior, I would forever appreciate it. I love her very much, I DON'T want a divorce, but I'm also not going to tolerate this kind of disrespect forever, I hope you can understand."
