By the way, I found out the hard way. Other moms lie! Especially about the potty training thing. In a culture where we're dependant on diapers, very few people get their kids really potty trained by the time they're 2 !! I chock this phenomena up to men bragging about size! :) I bet if you do your homework, those moms might have toddlers sitting on the potty sometimes. But totally off the diaper by age 2 1/2? I highly doubt it.
Just to ease your feelings, 2 1/2 is pretty young to expect a "boy" to be fully potty trained. From everything I've read, if you can get them trained and fully using the potty on their own, without accidents, you're son is one of the lucky few! Developmentally speaking, boys tend to be slower on the independent potty thing, so many experts recommend taking a laid back approach.
Ideas include, buying yet another potty or potty seat, but this time let him pick it out. Buy him one of those cute potty watches, where you set the alarm to ring at certain intervals (20, 30, 60, or 90 minutes). The benefit of the watch is he gets a sense of more control. Instead of you telling him to use the potty, he's going because his watch says it's time.
You don't mention whether you've tried putting him in regular undies yet, but this often "finishes the deal" for most kids and moms. Let him pick out his favorite character undies, put him in those during the day. If he has an accident in them, he'll be so uncomfortable, and hopefully upset enough because he "messed up" his buddies on the pants, he'll try harder next time.
If you're worried about leaks and smells, use those plastic lined pant covers made by Gerber, and put those on over his undies for a while, until he starts getting the hang of things. These are not the rubber pants that look like underwear, but the ones that seal shut with velcro and kinda look like a cloth diaper. You can find them at Babies R Us and Target. Usually, after a couple of #2 inicdents in them, he'll more than likely start keeping them clean.
One thing that worked for my kids was using this singing teddy bear that wore his own diapers. I put him on the potty first and squirted liquid from behind or left a mini candy bar (Oh Henry or Babe Ruth look believeable--I know a little bit much but it worked!) in the bowl to get the point across. The bear was preprogrammed to sing a rowsing cheer about successfully using the potty. Then I'd ask if they wanted to try, and they'd usually go right away, and we'd play the bear for them too. They loved it. The bear was created by Duke University and came with a really good potty training video with kids from ages 2 up to 6 both learning to use and successfully using a potty. The story centers around a boy who turns 4 and is having a birthday party. It's great for anyone who has "late bloomers" and really does a nice job without creating setbacks for parents of early learners.
One step ahead sold both the Bear/video AND the timed potty watch. At least they sold the bear about 3 years ago. I know for sure they still sell the watch. Go to www.onestepahead.com
Most important of all, from everything I've read, no arguments. Your husbands approach to ask rather than tell is the way to go according to the experts.
I hope some of this helps. But I'd say don't worry about what others say. He will use the potty when he is developmentally ready. Just be patient and read his cues. Unfortunately, it is alot of work. But if you can manage to keep the upper hand, he will come around if he doesn't come to percieve this as an opportunity for a power struggle.