That "all" is doing a lot of heavy lifting there.
You're away from home. Your OH has the freedom to wander from room to room, make food whenever they want, and to have a glass of wine with a friend.
Meantime you now live in a bedroom, have to negotiate to use the kitchen (and presumably clean it before you eat, otherwise you're leaving a mess for the other persons), eat your food (probably smelly to some degree) in your bedroom, on your lap, perched on the side of the bed, then sit on his bed with a glass of wine, listening to the OH's interesting day. I'm very much doubting there's a table, chair, and sofa in his room. And probably no TV either, so that's a laptop perched on your lap also (but obviously not at the same time as your food, so you probably eat in silence)
Ok - that's overegging it slightly, but I'll swear some of you have no idea what it's like having a home where you want to be, and a partner you want to be with, and not being able to be do it 70% of the time. And having work colleagues who do go home to the OH at the end of every day just makes it even more isolating,
I presume they already started taking turns cooking because, as you say, it was more sensible, but that act itself seems to be part of the issue being "a domestic intimacy".
OP is legit to make her concerns known but I do worry about the paranoia of MN'ers generally when DH is not 100% available for monitoring.