Why does my dog urinate in the house when I’m in a closed room with someone?

He sleeps in a different room and is fine when I leave for work, but only does a wee if I’m in a closed room with someone else or he can hear someone’s voice on the phone.. when I’m in a room alone he’s fine but if I’m alone with anyone else (especially my partner) he goes downstairs and urinates up my kitchen units. I’ve tried giving him toys and treats to keep him occupied when I leave the room, and have yet to invest in a Kong but I'm feeling really lost.

Hello!  Urinating is something that dogs may do when they're stressed; social hierarchy is important to dogs and it's possible that your boyfriend has arrived and taken over your dogs' natural position by your side;  this sounds stressful to me.  He doesn't sound bored, but displaced.  Rather than urinating to spoil your things, it sounds as though he wants to mark his own safe ground and surround himself and the territory he can get at with his own comforting pheromones.  When a dog can smell their urine in one place, they will often return to urinate in it in ordr to maintain the border.  Your vet may recommend particular cleaning chemicals to get rid of the smell at the level of a dogs' nose, as well as an insensitive human's. Ideally, you would consult a behaviourist.  This bad news is that anyone can call themselves a behaviourist - there are as many people quoting pop science and wanting to tell you how to bring up your dog, as there are when it comes to bringing up a kid.  People with the title 'behaviourist' sometimes recommend inappropriate things, in particular punishment which has been shown many times not to work.  Another problem is that trying one thing, then another, can make life unpredictable and stress a dog out more than helping.  Therefore, we would recommend asking your vets clinic to recommend someone with relevant, scientifically based behavioural expertise (they may be over the internet, not in person) who can intervene in a scientifically approved way. Please do avoid telling him off in the meantime; it really can escalate things. Best of luck!