I think you may have won the prize for most curious question I have seen in quite a while!
If your wife has read our literature and is a "fan" of Satanism, how is it that she is not
a Satanist in the first place?
If this is an issue of not making her affiliation public, I can assure you that many
of our members, myself included, do not make their membership public at all.
Beyond that I am rather stumped at why anyone would wish to support the CoS and not
consider themselves a member.
Perhaps this is something commonly done and I am simply unaware of it, but if there is a personal issue which is at cause (which is obviously evading me) please do not hesitate to email or PM regarding the details and the Church will certainly address it.
Beyond that, I of course defer to any member of the Church hierarchy who may have a more direct answer.