"So for the love of god (or the higher power of your choice for that matter), don’t put the future of your relationship in the trembling hands of your neurotransmitters,..."

You seem to imply that your readers have an "I" which is constant, consistent and can make and carry out decisions for their entire beings (including mind, body, and emotions). That is bullshit as a period of intense observation would make clear to them (at which point the possibility of directing the being actually just might begin to materialize).