There is definitely a drain on your body when you're making milk for two - even if one of them is only feeding once a day. The penny only dropped for me recently. If DS ramps up to more than one feed a day, I'm just knackered and grumpy and really snappy Wouldn't be so bad if we lived in a world that supported tandem feeding, but in this world, you get no extra concessions for BFing two, even with a partner who supports BFing!