Lots of good advice has been given by other moms,
but I want to toss another thought on the pile too:
Your kids will learn by the example their parents exhibit.
If hubby never helps, kids are likely to think they may not need to do more than work outside the home too (especially your son).
I want my kids to be SELF sufficient, not reliant on a partner's presence. Therefore, it's become important to
make sure my 16 year old son understands how to cook, how to wash his clothes (he started getting that job when he began to complain of my own method) and FINALLY how to get his own self up in the morning. (though his gf calls his cell to assist him with that, it's between them, not me).
He also does his own mending (and offers to do mine too)
and when he wants something ironed, he does that.
My fiance lived without a partner until he was 39. He's USED to doing everything himself. After being a single mom for 18 years, I was READY to let him, so awhile. He still irons his own shirts daily, and randomly washes dishes and cooks dinner. I like the example he sets for my son.
I agree with moms who suggest YOUR priorities shift too.
Time with kids is the most important. The mess will still be there. (and then you'll look fondly on the those toddler sized hand prints on the wall).
When my son's room looked like a tornado hit it,
I shut the door. When his friends came over, and there was no room for them in there, HE felt it was time to do something about it. It works well for us. (again, he's a LOT older than your kids)
When he was little, I worked the same method, but when it got too deep it became, "you clean it, or I will" and I used a trash bag. Once. That never happened again.
Baby steps mama!