Don't fight it. It is actually a tribute to your manhood and an evolutionary indicator that you are an Alpha Male.
You see, back when we were living in caves the Alpha Males were the only ones getting any. If Betas (or even Gammas like myself) went sniffing around the Alphas would quickly send us packing. Problem was that without any Betas the Alphas had to do all the work themselves and were not able to support all of their off spring. That was an evolutinary disadvantage.
But in groups were the Alphas napped during the afternoon it gave the Betas a chance to do their business. This resulted in a stable next generation and proved to be an evolutinary advantage.
So, enjoy your nap. And don't be surprised when you wake up if your wife looks like she needs a nap too.
LOL