Me and DH don't do everything together but we do most things. We go shopping together most of the time. It would seem strange for just one of us to do a big shop. If we just need a couple of things DH will often go to the shop on his way home from work or just go out on his own to get them.
We do go to each other's hospital and GP appointments. To us, that is normal. If either of us is seeing friends the other would never go.
About once a month DH has a 4 hour round journey to go and pick up boilers and often I will go with him. It means we can chat to each other on the journey, he is not having to make the journey alone and we will go for something to eat while we are out or stop off somewhere nice to look round. I expect a lot of people find that strange.
We have been married 42 years and still very much in love. We like being together and never seem to run out of things to chat about.
Every couple is different. We like to walk our dogs together. Again, it gives us a chance to chat and is time spent together with no interruptions like phone calls (DH is self employed and his customers ring all times of the day and night).
A lot of our neighbours have dogs but hardly any of them walk them together. Some there is only one that ever walks them and some both walk them but always separately. None of them have young children so they could walk together.
I do have neighbours that take the doing everything together to extremes. They have 4 young children. Neither of them work so they are together all day every day. They all have to go shopping together, often 2 or 3 times a week. Even during lockdown they all went to the supermarket. They can both drive so no reason they all need to go.
Last month I saw them putting the children in their car. It was about 6pm and I asked if they were going anywhere nice. They were going to pick up a takeaway! Now I do think that is weird. Just why would you drag 4 children along when just once of you could go?