We need to stop looking at this from the perspective of loads blown. I'm sure some of us that go to round three with a chick might not bust, but we still keep fucking. That's the point. No man has an endless supply of nut in him. You need time to replenish, but you still like banging. Sure, your dick might be a little tender, but that isn't life threatening. As long as you can keep getting hard, you can fuck if you want to.
"The best kind of pride is that which compels a man to do his best when no one is watching."