My wife has an Equinox+ membership for the at-home SoulCycle bike ($40/month) and her Amex Plat effectively reduces it to $15/month.
I just had a thought - I also have an Amex Plat (separate account, not AU). Could we split the charge to cover the whole thing?
It would probably require a monthly phone call to Equinox every month, but it's an intriguing idea.