In my case, STBEX and I still have a common e-mail address that school and others can use for kid-related information and invites so that both of us are clued in. For instance, S got an invite for a sleepover next weekend (when STBEX has the kids) so this saves STBEX having to inform me directly.
Concerning bank accounts: We still have two common checking accounts active while each of us now have an additional one that the other cannot access. It makes money transfers a heck of a lot easier if there is still a good degree of trust in that arena. Fortunately I have that but I know it could always get a heck of a lot worse...
Me 52, STBEX 52 D 17, S 12 M 20 years Em Sep since 2002, Phys Sep Sept 2009