I think we should bear in mind that we only have Andy's word for it that Megan can't/won't clean the house, clean up after the cats, etc. It could be that she normally does contribute, but he's gotten the place into such a state that she can't deal with it alone. Obviously whatever's going on with the cats didn't happen overnight, but the rest...

All I can think of is Abbey's story of how hard Diamond worked to make their apartment look nice for the NZ actors who had to stay there when Tent Moot fell apart, only for Andy to trash one of the bedrooms and blame it on Bob. He even pissed on the mattress so as to make it completely unusable. I wouldn't put much past him.