I am not a therapist or a supervisor so I am far from an authority on this issue. I do think about it a lot and want to share my thoughts.
I think that with some limitations on the nature of the friendship openly acknowledged and honored it is at least theoretically possible. Therapists and other people in helping positions in small towns often have to navigate all kinds of dual relatonships with their clients including friendly interactions outside of sessions, and they seem to do it just fine. I believe there are ways to set and adhere to certain parameters for what the relationship will be at this particular time vs. that other particular time.
Doing this successfully would require a high level of personal and professional integrity on the part of the therapist. A very high level.
And right there is the rub. A therapist with a high level of integrity would also understand that the rules against engaging needlessly in dual relationships are there for good reason and really do protect his clients. This means that a therapist with the required level of integrity will neither be soliciting his clients for outside relationships, nor encouraging his clients in wanting this.
This means that… if your therapist is in any way inviting or encouraging a friendship with you in addition to the therapeutic one, or in place of it… then it’s time to put on your running shoes and sprint in the other direction. That therapist does not have the level of high personal and professional integrity required to make such an arrangement work and not harm you. It might feel good… and you’ll get burned.
I so hate it when my idealized view of people and the world crashes into messy reality!
But yeah, all that to say that therapy and friendship really shouldn’t mix.