Basically the entire song is about a guy ejaculating. "Dying" is a classical euphemism/idiom for ejaculation. If you cut out the chorus, the first section describes the bedroom and his surprise at "coming to this", which refers arriving at this situation with this girl or again the act of ejaculation. In the next section he implies that she's been with several other men because he's just "a name on a list" which doesn't stop him from "blow{ing} it again". Then he's too exhausted to go on "Cause I've been thrilled to fantasy one too many times" so she's getting all the enjoyment "no give and all take". The last section like the chorus reflects a little regret or shame, but obvious enjoyment.