I did. I hadn't intended to, but not for any real reason other than the admin, frankly. One day it came up in conversation and it turned out it mattered to him. A little. So I did, given I didn't really mind and it made him happy. He doesn't ask for much, ever. In fact, he didn't ask for that, either, just said he would like it if I did and left it to me.
I am myself no matter what I call myself. It was my choice. He does not own me, and knows it. So why not?
Until recent events, I had the occasional twinge of regret that I now have a British surname and am no longer obviously from somewhere else - like a loss of something that made me different (my first name exists in English, but my surname was very clearly French).
Sadly, these days it makes me feel safer to have a British name.