This is a question I asked based on problems I struggle with as someone raised Catholic as part of a generation taught more about science than any generation before me. I can't simply ignore science. So I ask this fundamental question:
If I were to sit down with my wife and watch TV, it would be a form of pleasure and bonding we share together, which is not a sin. But if I were to have sex with my wife without the intention to procreate, it would be considered a sin by the Catholic Church.
In science today, we have proven that love is not some magical thing, it's a biological mechanism triggered chemically, and emotionally (emotion also being a biological mechanism).
The conventional view in biology is that there are three major drives in love – sex drive, attachment, and partner preference. The primary neurochemicals (neurotransmitters, sex hormones, and neuropeptides) that govern these drives are testosterone, estrogen, dopamine, oxytocin, and vasopressin. (Source : Wikipedia, see it's own citations 1-7 which are largely peer-reviewed scientific journals).
According to studies, part of this biological mechanism that causes two people to become emotionally and romantically attached to each other is induced during sexual intercourse.
In humans and bonobos, the female undergoes relatively concealed ovulation so that male and female partners commonly do not know whether she is fertile at any given moment. One possible reason for this distinct biological feature may be formation of strong emotional bonds between sexual partners important for social interactions and, in the case of humans, long-term partnership rather than immediate sexual reproduction. (Source: Wikipedia, with citation to Encyclopedia of Human Relationships.
If a couple is financially or legally unable to procreate, and does not have sex for this reason, that chemically induced biological bond is never refreshed. In other words sex is scientifically proven to strengthen the bond between husband and wife.
So as a student of science, you can see why I have difficulty understanding this teaching of the Catholic Church.
Why does God not approve of a loving married couple enjoying pleasure and passion together via sex, for the sake of strengthening their bond as a couple? Has the Catholic Church responded to the argument that sex between a married couple can strengthen their emotional bond? Is there any official literature or doctrines that address this argument specifically?