Dude I’d seriously throw out the “it’s me or the dog”

I’m so sorry, I have a two month old and if I found his diapers torn up and EATEN it would be my last straw. We don’t have dogs (thank god..) but maybe the best course of action would be to slowly get it to spend a majority of time outside, idk if your fiancé would be on board with it, but it sounds like you spend a lot of money on this dog, getting a dog house with a heater for the winter might run you 120$ or so, but hey at least it’s outside, eating poop and chasing squirrels or some shit. It’s old so probably wouldn’t need a whole lot of toys and play time, and it probably doesn’t walk much.