A Google Calendar
No one should be expected to remember by 6 p.m. a plan that was relayed to them at a sleepy 6 a.m. Try a coworkerly approach: Share a Google calendar, with all the important events clearly noted. Then, if nothing else, it's all written down, and you have evidence when your partner protests that he was half-asleep when you reminded him about cousin Cathy's coed baby shower. Not that it would ever come to that. But just in case it does.