Who knows about cats? (long)

My cat Snapple recently decided to stop urinating in the litter box and instead, every morning goes in the hall outside the bathroom. I wake up every morning lately to hear FH cursing that 'he did it again' (and threatening to get rid of him ), and with bleach and scrub brush in hand, I roll out of bed and burn my eyes and choke on the bleach fumes just so my apartment doesn't get condemned. Thank God I don't have carpet or wood floors or anything like that....

We've tried so many things to get him to stop. FH says he's just being spiteful. At first I thought I wasn't paying enough attention to him as I was to the other cat, so I make extra effort not to ignore his cries (he's a loud cat, always has been) and spend an extra few minutes playing with him every morning and night. No good.

Then we thought maybe because his dish was empty and he was just being nasty - so we make sure his dish isn't empty. That's not it either, although it worked for a few days.

I moved the litter box to the spot where he goes and he just moves about a foot away.

Yesterday, I left the house for school at 6:00 - FH was walking up the block and saw me pull away and when he got upstairs at 6:05, Snapple did it again! I don't understand why? Except for this behavior change, he seems healthy, he's eating, he's still fat as ever, his nose is wet and cold, he still purrs like a madman whenever I pet him...I just don't know what to do. I am bringing him to the vet on Monday to get him checked but I wonder if anyone has any advice???