Mark, all class AB amplifiers are closely comparable in their power efficiencies and it's unknown how small any difference between the Denon and the Emotiva might be. Given equal efficiencies there would still be a bit more power used when a second amplifier is turned on because even when no speakers are being powered the amplifier might use 50 watts or more at "idle". So, using each for two or three speakers would use a bit more power because of the idling factor.
If you actually used louder sound levels because of the Emotiva that would of course consume more power. But if you value your hearing and keep the sound levels constant there wouldn't be any additional power usage(other than the factor mentioned above)or any audible difference resulting from the addition of the Emotiva.
By the way, you ask God to help you resist this urge, and if you wish I'll pray for you or even have a Mass said for your intention. Keep in mind however that although God answers all prayers, the answer often is no.
Enjoy the music, not the equipment.