Turning off itunes match for a family member

I have a family member (wife) who is on my family share plan with iTunes. This works, except she is also a member of iTunes Match. 24.99 a year, auto renew. I also am a member, and one is enough, because her music is shared to me. I don't need two iTunes Matches, but hers is coming up for renewal and I can't seem to turn it off. Hers renews in July and mine in January.