followed with ‘I wasn’t aware is so important to you. I didn’t want to insult you and if you felt so, I apologize. The word fuck is one I use very often, but I’ll try to control myself around you’
Note I didn’t insult the coworker (no fuck you or fuck off), but simply said ‘fuck’ out loud due to a job error.
Really not a good apology.
It comes off as looking down on the other person.
So it is all just bad behaviour on your side. You can apologize for that: Your own behaviour. NOT the coworker’s interpretation of it.