@SarahSmith2023
It's not controlling or weird. We both prefer to know how long the other person is leaving for as then we can make decisions about what to do ourselves.
It's annoying if you're watching tv/playing a game and you don't know if they're nipping to the loo or going to have a shower & go to bed or walk the dog or call someone.
It's good manners, sorry you're not acquainted with them. 💁🏻♀️
I think there's some middle ground to be had here. I don't think it's necessary to announce you're going for a wee 😬but if you are going in the garden for an hour, then yeah, just say 'I'm popping into the garden for a bit. Watch what you want on the telly.' Or if you're off to your mate's house and aren't coming back for 2 hours, then of course you should tell your partner. With an estimated time back too. As you say, it's courtesy and politeness.
I never announce when I am going to the loo, or for a drink of water from the kitchen, but when I get up off my chair, DH ALWAYS ASKS 'where are you going?' Every. Single. Time. Suffice to say, he always announces everything HE is doing... 'I'm going to the loo.. do you need the bathroom?' (When he is just going for a wee!) And 'I'm getting glass of squash,' and 'I'm getting a biscuit.'
And when he's off work, around midday he says 'I am getting myself a tiny lunch.' He calls it a tiny lunch every time. 
Comes back with 3 rounds of cheese buttie, a bag of crisps, a 4 bar kit-kat, 3 biscuits, and a yogurt. I would hate to see what he had, if he had a BIG lunch! 😬
Conversely, some years ago, DH used to have this annoying habit (before he got a mobile phone about 12 years ago,) of popping out in the car before I got up, and not leaving any note to say where he had gone. When I got up he was out. He was at the shops, or had gone for a walk in the town park 2 miles away, or to a relative's house or friend's house... I never knew where.
So I would get up at 9.00 to 9.30am on a Saturday, and not know where he was or what time he'd be back. I know this sounds OTT, but I found it a bit controlling and manipulative, because I couldn't do anything specific, because I didn't know how long he was going to be. He never told me. Never said the night before that he was going out, and never left a note,
So I couldn't put a film or a box set on, or blitz the house, and clean it from top to bottom, or really relax and chill, because I didn't know what time he was returning. I just sat there twiddling my thumbs, and glancing out of the window to see if the car was coming up the road.
I told him it irked me, and he said 'I didn't know I had to get permission to go out, and leave a note saying when I will be back, which is impossible because I wouldn't know anyway. Could be an hour, could be 3 or 4.' He refused to get a mobile phone too, so I could just text him to ask roughly when he will be back. I know this sounds odd, but probably 99% of the time I go out, I can give a pretty accurate estimate of what time I will be back. Within a half hour window for sure. So I couldn't understand why he didn't leave a note. It felt very manipulative to me. Keeping me hanging, and wondering, and unable to relax and enjoy the free time.
This one time he did this - and the last (about 12 years ago,) I went out. I got up at 9am and the car was gone, and so was he. No note, no message. I packed a backpack up with food and drink, and got a taxi and went with the kids to a nature reserve for a few hours, then got the bus back to our local small town and had a look around there. Then got a bus back home. Left my phone at home, switched on, so if he rang it, he'd see I had left it at home., and he had no contact with me. Let's see how HE likes it, not knowing where I am! (And when I'll be back.)
Came back at 4pm. He was purple in the face with rage, as he had been frantic all day wondering where me and the kids were. I just said 'oh, I didn't think we left messages or notes when we went off out, and no information as to where we are. That's what you always do.
tl;dr. He didn't do it again, and he got a mobile phone shortly after.