Oh do grow up! I am certainly not "making a martyr" out of myself! I will try to explain it just one more time.
It's as simple as this - the more people there are in a household, the busier it is. That's not rocket science is it? The more pressure on the bathroom (fortunately we have three, but everyone wants to use the freestanding shower in the en suite, not the one over the bath). Five people needing access to the kitchen. Five people wanting to use the washing machine and tumble dryer, and inevitably they all want it at the same time. Five people getting ready/out to work/WFH/attend uni every morning. Five people inevitably create more mess than two or three do.
There's one TV in the living room (we no longer have one in each room as we did at one time - and we can use phones/laptops of course) but that's the main place to access all the channels/Netflix etc, and it's at a premium. There's one sofa in the living room, one sofa in the family room. Sometimes I'd just like to lie on the sofa and watch crap - but we don't all want to watch the same crap! I can't abide Love Island, ghost stories or Family Guy. They don't want to watch Location Location Location! With bedding/kitchen utensils/lamps/tables etc etc etc from 2 flats having been brought home, every inch of storage is under pressure, and the house feels just overstuffed and messy. The dishwasher is on all the bloody time it seems (no matter who loads/unloads it).
There's the lift giving, from nights out, trips to/from the airport and work. That does work both ways as two of the three drive (obviously and inevitably we paid for the lessons and for DC3's car insurance; DC1 has their own car), so DH and I do benefit too. I picked DC1 up from a flight late on Sunday night. DC2 off the train from a night out last night. DC1 collects DC2 from work though on their way home. DH drops DC2 off to work every morning. DC3 gives the other two lifts and takes my car to work, leaving me without a car (if I need it though I will tell them they can't use it but I can't decide to do something last minute on a whim). DC1 ferried me to and from concerts recently. DH left the three of us to the airport when I went on holiday for a week with DC1 and DC2.
They are all very good about keeping in touch, but you can never let go of that element of not being able to settle to sleep until they are all in safe no matter what age they are - or I can't anyway (they don't take the piss at all and I'm glad when they do go out after all the privations caused by Covid in their young lives).
The last year has been a bit of an epiphany for me. I've always wanted all my chicks in my nest (obviously they've got on with their lives as they should do and I have encouraged it but I was always happiest when they were at home). I think I've realised that my nest is now a little too full? All three of them want to be out there living independently, and that's what they need to/should be doing. Circumstances just don't allow it and they are welcome here as long as, and whenever, they need to be. When I was DC1's age, I hadn't lived at home other than in uni holidays since I was 18, and DH and I were living and working in London.
They are all very close and have each other's backs but they do bicker too! Sometimes I just want to run away.
Also someone has to be the co-ordinator to ensure there's always bread/milk/toilet roll. That's me. I do my grocery shop online and the kids are happy to nip into Tesco if we run out of something, but ultimately it's down to me to make sure that we have what we need, and cater to everyone's taste.
I guess I just feel that, in some ways, organising life is almost as busy as when they did activities 5 nights a week when they were younger, and I'm older with various health conditions so I don't have the same ability to cope with it.
I don't think I can make it any clearer than that?