Advice!

Brittany • taking my journey day by day
This sweetie pie is Tesoro; he is a year and almost two months old
He is the youngest of my 3 purring babies.
I love him to pieces. 
But he keeps urinating on my floor.. I don't know how to make it stop. He gets plenty of attention and love, he has a very steady stream of Rhine so I know he doesn't have a UTI.
We bought a bigger box as we thought our last one was too mall and that had been causing the issue but it solved nothing.
If the box is dirty he'll urinate on one area and then poop on another. 
But he'll do it even when the box is CLEAN. We aren't always home so cleaning the box after every time each of my cats goes to the washroom is illogical. I don't know what to do, I don't want to give him away but I can't have him peeing on my things.  
Please help.