Thanks for the additional information. Unneutered cats usually spray rather than squatting and urinating. I really think he needs to see a vet. If he has a urinary tract infection or if he's just starting one, his bladder will feel so uncomfortable he'll want to relieve himself wherever he happens to be, rather than going "all the way" to his box. I'm especially concerned because he urinated on you.
If it turns out that this is a behavior issue, here are some things to try.
--- Put a box in his preferred location. It's possible that he doesn't like the location of his box and would rather eliminate somewhere else. When he's using the box consistently, you can move it, inch by inch, to a location that's acceptable to both of you.
--- If your box has a hood or top on it, take it off. The hoods trap unpleasant odors that only cats can smell. Also, cats like to see an escape route from their boxes, and that's not possible if the box has a top.
--- Try giving him a box with Cat Attract
litter. A lot of people have very good success with this. You can get it at any pet supply store.
--- He might prefer an empty box with no litter in it at all. Put a puppy training pad in the box to make clean-up easier for you.
I hope some of these suggestions help. If you'd like to talk more just write back to me.
I meant to send this as a request for information so you wouldn't be prompted to pay for a second answer and clicked on the wrong button. Don't pay for both answers!