DH and I have access to each other's FB accounts and phones anyway: not that we use it (or at least I don't), but as there's nothing to hide there's no point in changing passwords or suchlike so the other cannot access it. (DH did freak out when he logged into my e-mail instead of his and started shouting that he didn't know who X was who was e-mailing him: my friend e-mailing me. All happy again.)

However, if you're happy without access then don't ask for it. If you don't want it there is no point.