The institution of marriage has certainly been under assault for a number of decades now. The contraceptive mentality has led to promiscuity, infidelity, and a laundry list of other negative consequences. This lifestyle of "hooking up" has been celebrated and propelled to the forefront of our minds from an oversexed media and entertainment culture. Something good and holy has been demeaned by those who want no restrictions or limitations in their sexual pursuits.
Anytime we start messing with God's natural design for life we reap chaos. Humanae Vitae was ignored or ridiculed immensely back in 1968 when the encyclical was published on July 25. It is time to take a fresh look at the wisdom contained in this document. I would encourage each of you to read it in its entirety to see where our society has gone in the 47 years since its publication.
http://w2.vatican.va/content/paul-vi/en/encyclicals/documents/hf_p-vi_enc_25071968_humanae-vitae.html
Has adultery decreased in modern times? Has the divorce rate declined? Is the family better off now than it was fifty years ago? Do some reading and research of your own to see why the Church teaches what it does.
http://www.usccb.org/issues-and-action/marriage-and-family/natural-family-planning/