>So if I focus all my resources on having sex, then effectively I take resources away from longevity. I take them away from surviving for longer, and so I shorten my lifespan almost deliberately in evolutionary terms.

This is a very interesting statement - in some of the Esoteric Teachings I have read throughout my life - they specifically say that masturbation for simple pleasure (ejaculation in males) -- drains you of your life essence and is seen spiritually as a selfish-wasteful use of your life - and this shortens your lifespan and reduces your spiritual power. (additionally, doing very deliberate things with sexual energy is a basis in sex magick)...

The idea being that you're pulling life-force from yourself and then 'projecting' intentionally toward what you're doing with that sexual energy -- which would be interesting if you were draining energy from mitochondria in general.