Pretty sure I am going to get shot for this but here goes.
DH and I have been together for 10 years. He has 2 kids, nearly 18 and 15. I have 2 kids, 11 and 13 and we have DS, 2 years, together. My kids are here 100% and his kids 50% of the time. They all moved in with me about 5 years ago and luckily we have enough room for everyone to have their own bedroom. I gave up my home office to allow his DD, 18, to her have own room. For reasons I won't go into but stem from me having had a very difficult divorce from my ex, DH and I don't share finances. The house was mine and stayed in my name and he pays a very low amount/nominal £500per month in "rent", the idea being that he should have surplus income to invest elsewhere, get a buy to let etc.
Anyhow, my work have just announced that we will not be returning to the office and will work from home permanently from now on. I have a demanding job with lots of calls/papers etc and have so far worked from our bedroom but now that I am permanently losing my real office (at work) I really want to have one at home. DSCs are only here 50% of the time and each have a room each at their mum;s house so I am wondering if I can reclaim one or both rooms as my office, especially given that DSD is nearly 18. She would always be welcome to stay but how long are we expected to hold a dedicated room for her, especially when she also has a room at her mum's house? Seems a bit OTT especially in London when rent/mortgages are so expensive. I am pretty sure that DH will not hear of this but it really adds to my stress levels not having a dedicated space.