Hi there.
I'd just like to say, Mocha is 8 months old and fully trained about a month ago. I fenced her and used a pee pad with the tray for about 2 months. She used to go on mats but now no more. If you use the tray, it might help him know the difference between where he should go and where he shouldn't. She used to have accidents like twice a day for MONTHS. Situation was very much like yours. I did not give up.
Fencing him might be the answer here. Keep him in a pen, have water, food, pee pad, and his toys in there. I know you said your husband doesn't want a dog that has to be kept in a pen, but this is not forever! If he doesn't wanna do it, then what does he want to do instead that will help with this problem? Please remember, it's most likely not the dog. When people has trouble housebreaking a dog, most of the time it's the humans that are making mistakes with their training methods.
To be honest, I am very bad with discipline and consistencies too. Trust me, I am the very worse dog trainer ever. But I trained her alone. ALONE. I also cleaned up all that pee/poo alone. So if I can do it, I fully believe you can do it too.
Don't give up. Rehoming him should be the very last option. I truly do not believe a Yorkie is any more trouble housebreaking than any other dog. Mocha is my very first personal dog, my very first housebreaking, but I DID IT. YOU CAN TOO!! Good luck!!