There are pockets within our society now where the illegitimacy rate is reaching 90%, and sex as an activity divorced from reproduction is just as widespread throughout most of our society. Those who are contributing to that rate (especially men, but also the women who are participating actively by sleeping with and/or bearing multiple children from multiple men) apparently do not place the same degree of value on these things as we do. Until they experience a mighty change of heart that changes their actual behavior, I don’t see that changing - especially if we continue to empower them financially in the name of “taking care of the children.”
As a society, we have trivialized sex to such a degree that we commonly use the term “sexual partner” - which, by its very nature, offers a “legitimate” option to a “wife” or “husband” and reduces “mate” to its biological definition. When “partner” no longer even implies a contract of any kind (but merely contact of a certain kind), I’m afraid the only choices available to change people’s actions are severe social measures (like eliminating welfare payments and/or levying taxes for any children following the first one to someone who was receiving welfare at the time of - or within an established time frame prior to - conception of the additional child) or deep conversion to the Gospel standard of chastity. Given our obsession with enabling illegitimacy and taking care of all children, regardless of the circumstances of their birth (a twisted version of compassion, imo), I’m not optimistic that the first will happen; the latter might be the only option - and that is a very difficult thing, as well, since it requires an unyielding call to and acceptance of repentance.
Again, that simply highlights the need to find a way to make an argument that appeals to the spirit, since we are losing the argument with those who are focused on the body. I just don’t see a way to change or “control” sexual behavior if we focus on the physical / political reasons for chastity. We must maintain chastity as a religious principle.