Hi - well firstly I would book him into the vet for a check up to ensure he hasn't got a UTI. If he hasn't then perhaps look at providing a litter tray for him again at least for the winter months if he is reluctant to go outside in the cold....and who wouldn't be?!

It could be a stress/behaviourial thing but the fact that he is doing a full wee rather than a spray makes me thing it just may be a UTi.