Hi, H.!
Well, you'll likely get a variety of responses on this, but all I can tell you is from my own experience, so here goes...
First of all, while I really appreciated the super absorbency and convenience of diapers and training pants, I think these devices are 100% to blame for the length of time that kids are wearing diapers these days. Back in the day when we were all wearing icky cloth diapers, there was an impetus to get out of those awful things and potty on our own so we didn't have to "wear" our uncomfortable excrement around.
These days, kids can feel so comfortable in their diapers that there's no real rush to get rid of them.
We started potty training our daughter at around 18 months old. She was receptive to the little potty we used, and she had a whole collection of books in the bathroom so that she could sit, read, and enjoy the experience. The older she got, and the more communicative she became, the more insistent we became that she start using the potty and not soiling her diapers. However, the more pressure we put on the act, the more resistance we started to get.
We had a travel potty in the car, which was a wonderful device that used ziplock gallon bags and folded up into a briefcase when collapsed. She loved using that, and I'd give her a little Hershey's kissable if she went pee pee and a malted milk ball for a poo poo. Also, in summertime, she could sit on her travel potty and blow bubbles. So, there were plenty of rewards and incentives to make the process fun.
Nevertheless, the older she got, the more concerned and frustrated I became that she wasn't initiating the potty trips. The more I tried to exert control over it, the worse things got 'til she was actually using twice as many diapers as she had been.
She's always been an incredibly independent child, and I think it really aggravated her that I would try to control this aspect. We'd remind her every hour or so, and try to make the rule that she'd need to go potty before leaving the house, etc.
Anyway, finally, while on a trip visiting my family, she declared, "When I get home, DADDY is potty training me!" We returned home, she made the mental decision that "Daddy" was going to train her (which really just meant she was going to do what she'd already been taught), and she was potty-trained in 3 days. She was a little over 2.5. I'd told her that she couldn't start school if she weren't potty-trained, and she got it done, just in time.
I've said this to other moms frustrated with this process: for whatever reason, for many kids, if not all, this is something that THEY have to decide they want to do and THEY have to do it. You can give them all the tools and tricks and skills, you can give them lots of rewards and encouragement, but, at some point, there has to come some impetus that makes them decide that THEY want to do it. Each kid gets to that point their own way.
My daughter's good school friend JUST potty-trained this week, and she's over 3. I know it's frustrating and difficult.
Basically, you and your husband need to keep your cool. You need to be a team -- don't opt him out of being part of the process because he has a lack of confidence. He needs to develop the same confidence as you have. That's part of his job! You need to both be familiar with what you consider the "bathroom routine" and maybe determine some new rewards for your daughter that can gracefully encourage her back to the potty. Maybe try reading a new book to her there or singing a song or granting her extra play time or a movie or tv time -- something new. But, whatever you do, you need to be unified. And it needs to come to the point that you're not forcing your daughter to sit on the pot but that she's willingly going there because she knows it will be a pleasant place to be. I'd say that's step 1.
Another tactic we tried with our daughter was that she would get to use a certain number of diapers or training pants per day, and if she went over that amount, she'd have to wear underwear with plastic pants over it. Of course, that's miserable, and she didn't like it, so there was an incentive to use the pot and not mess up the panties.
I hope some of these suggestions help you! Don't lose heart -- you'll get there!!
:)
H.