Hi! I will try and help with my limited experience.

 First and foremost, is Ruby neutered? If not, he is most probably being territorial and there’s not much point in trying to litter train him until he’s been fixed.

It could be territoriality even if he’s neutered. He wants things to smell of him and not Monkey. He may want to dominate. In his previous home, what did they use as litter for him? It could be he doesn’t like the litter you use, or it could be that they trained him on towels – and there’s not much difference between a bed and a towel.

 I expect more experienced people will be along soon, however I would clean up his current pee but not enough so that it removes the smell, and rub some objects in the room on his fur so that they smell like him. This way the place will smell more like home. Put some litter with his pee on it in the litter box also. If you catch him in the act, pick him up and put him in the litter box. You may have to confine him if this doesn’t work so that he doesn’t exhibit this behaviour at all – have you a small room in which you can keep him for a while, maybe one with a chair and table so you can sit and work or read with him? You can cover the floor in newspaper so that he does not pee on the floor. With any animal, the more they do the behaviour they more they will carry on doing it. You have to break the cycle.