Hello Submax: I noticed this is your first post here on PC. So... welcome to PsychCentral! Anyway... I'd be really suspicious about that therapist & her supervisor... no... I'd be more than suspicious... I'd run the other direction! They may simply be viewing you as a lab rat, so to speak. It might be fun & interesting for them... but not at all beneficial to you.

I think the real question here though is what, if any, impact is your fetish going to have on your marriage; & how will you & your wife handle it? Is your wife going to be accepting of your fetish, or is this something that could drive a wedge between the two of you? Are you prepared to accept the consequences if it does?

You wrote you have zero desire to stop being beaten. And as growlycat wrote fetishes do not go away; at least I believe that is the general consensus of opinion on the subject. So, while seeking therapy in an effort to "cure" yourself of your fetish probably doesn't make sense, there may be some need for both you & your wife to seek some counseling / therapy services in an effort to determine if-&-how your fetish can be accommodated while still preserving your marriage. I wish you both well...