I have heard that if you and ur dog/pup are continuously together and then all of a sudden you go out more often then what your dog is used to, or even going out for that matter, your dog can pee/poop or chew in protest.
Does he spend less time with the dog then he used to?

If thats the case then i reccomend going out for a very short amount of time without your dog and then increasing the time gradually.
maybe that will help.

Gorgeous looking staffy btw