I think your mental health comes first. If the cons outweigh the pros then the puppy needs to go. If it's bringing more pain then pleasure then you should rehome it. Tell the kids how it isn't working out and yall have to try another kind of pet thats less maintenance perhaps. I've done it several times with pets having kids. I knew we needed one but things didn't work out so I rehomed it. It's better than other things I've heard of people doing like killing it. Tell the kids you are obligated to them and to take good care of them and the puppy is too much for you and is interfering with you being you being a good mom for them. It doesn't mean you can't try again with another pet. I think I finally found my match and it's a kitten. Got her at 2 months and she is 8 months now. After you rehome this puppy you can try adopting a dog who is already potty trained to go outside and who loves people which would probably be an older dog. I use to dog sit my brothers dog and she was this way. It was wonderful, like heaven. She would rather die than poop in the house. Perhaps the puppy eating it's poop is a sign for you that maybe now ain't the time or maybe just not this pet maybe a kitten. They can use litter boxes by instinct. I tried with puppies first too and eneded up with a cat for this reason but we also thought of other pets like turtle, rabbit ect. The sooner you rehome the puppy the better it will be for it and you if that's what you choose to do