Co-worker Adjustment Period

A couple of weeks into the new job and I have adjusted to getting up way, way before the birds,  attempting to look like a normal human being and spending many hours locked up in an office.  I have managed to find things to amuse myself other than iv bagging coffee into my veins.  Who has NOT adjusted is my one ex-coworker who has now decided that if I am not going to be around all day long to meet his every need, he is going to show me and forgo the litter box and do his business in all other areas of the house.  Its kinda like coming home to your own special easter egg hunt but its not bloody easter and the eggs are cat business number two (on a side note the whole house smells as well!). I have threatened to leave him in a cat diaper all day long but he just gives me a look like "just try it lady".  I could just see the result of that.  There would be cat diaper and cat crap all over the house when I got home!  For now the score is Ex-CatCo-Worker - 1, Me - 0.