Girlfriends are paid subscriptions: it loves to upsell you on premium features, sex can be removed from the catalog without prior notice, and you never know before subscribing if you're finally joining a service that offers anal and costume play like the competition.
Then you find out there's pay per view, and sometimes a service offers things to non-subscribers only, and doesn't notify the subscriber...
(of course, if you're rich you can skip all of this and just buy physical media, put it on a shelf and own it forever; ok I might have gone too far with this analogy. LOL)