I have a fair number of people I can call to dive with. There are a handful I will dive with on certain dives like deep, deco, cold water. Then there are the dives I don't need or want a buddy on. That now is the vast majority of dives I'm planning for the future now that I have retired from teaching.
Even with the handful of people I would do riskier dives with, I was never able to totally relax. Even when we did some benign trips to the quarry where we never got deeper than 20 - 25ft, I always felt like I was "on duty" watching out for them in some way.
Only solo can I truly relax. Shallow quarry or deep deco with wreck penetration planned, if I'm alone I am relaxed and at peace.
I am going to be diving with some students I trained over the years. Not as an instructor, just as a buddy, but I know that I'll be watching out for them.
For an ethical instructor, all the ones I've spoken with feel a sense of responsibility to the person they are diving with above and beyond the usual dive buddy dynamic.
I think that's because for so many years, not having that sense of responsibility could result in some very bad legal stuff happening to you.