Every night between 3 and 4 am, my husband gets up and goes for a wee in our en-suite. It's a fairy big bedroom and a big bathroom, so it's not like he is 'in the room', but he wakes me up and I can't get back to sleep.
He's been doing it forever, but we have a 4 and 2 year old who wake for the day between 5 and 5:30 and it's exhausting. If I'm lucky enough to doze back off to sleep, it's never long before the DCs are up so I'd only ever manage to grab a few minutes max.
He tries to be quiet but we live in an old house which creaks. I wouldn't mind if it was the odd night here and there, but it's basically every night. My day started before 4am today 
He seems to think it's just his body clock that wakes him up and he needs to go for a wee to be able to get back to sleep
I told him to stop drinking anything after teatime to see if he can break the habit - like when you are trying to get a toddler dry at night!
So:
YABU - let the poor man have his wee and go back to sleep.
YANBU - he needs to train himself to break the habit.