The sexual blueprint you describe, Kikapu, gives men the biological imperative to reproduce and 'spread his seed'.
This implies that the continuation of the human race is the most important aspect of sexual relations, and overrides all other considerations; trust, love and so on.
I always find this argument disingenuous because if it's the most important thing, then why would men use contraception during one night stands or whilst cheating? Something the blueprint left out?
Why do committed relations exist at all, if the male's sexual blueprint is so dominating and so all-powerful?