He always does this. I don't see a reason to lock the door as I'm not against him coming in if he needs something/it's something important. But maybe I do need a lock.
He's always popping his head round to say "Hello darling, you look so beautiful" or "Hi!
How are you?" 
He's very sweet but I feel incredibly irritated now. He won't stop, even though I have said I'd rather him not come in whilst I'm on the loo.
This lasts for all of a week before he starts doing the same thing. Or he will only come in to get something but then get sidetracked and start asking me how my day has been.
AIBU to get very cross next time/fix a lock?
Comparable to this is him looking at wedding related things for the wedding and wanting me to look and aww with him 