I can understand your frustration on this, you do seem to be in a catch 22.
"The kids (now D18, D16, S12 and S8) view them as a joke, because they know that we won't follow thru on them"
This is just a thought here on this...I know you are sick of being the enforcer....BUT...yes there's a but here. If you do not stand firm, you give her that out to say you don't do it. A good friend of mine experienced a similar problem....only she was the enforcer, her H was the one who always caved. She finally put her foot down and made it VERY clear to her kids (2 teens, 1 younger) that if SHE gave them chores and they didn't follow-through on them then SHE would enforce the consequences...Dad couldn't let them off the hook on this.
Now, I know this will be a HUGE pain for you...BUT (don't you love those buts). Perhaps you need to do this too....even if your W caves and does what she's asking them to do...consequences still need to happen for them not doing what they were told/asked to do.
Just a thought here...but perhaps you could tell your W you want to try an experiment...then outline the above. Where there are still consequences for the kids if someone else does their chores and they don't. I know that will be VERY tough with older teens because at this point I believe there is a respect issue at play. But make it clear to her that YOU will enforce the consequences if she doesn't...then do it. Make it VERY clear to your kids that mom can't let them off the hook, just as you can't let them off the hook if she sets something up with them.
This is a respect issue between you and your W as well. YOU MUST BACK EACH OTHER UP ON THIS! Your kids need to see a united front here...or they will not respect you on it and take you seriously.
Do you think your W would go for this, if you put it to her as "Honey, I know you feel overwhelemed with everything you have to do. I want to try something but I need your help to make it work....."
I don't envy you this one....but with a united front you two can address it....then she wouldn't be able to use it as an excuse.
