There is a distinction between a puritanical attitude towards the body and a Catholic understanding. Often the two are confused. First let's start with Adam and Eve. They sinned they disobeyed God. The Protestant view is that they lost not only Grace but also their humanity. They fell beneath the good human nature which God gave them. Later, when God through His Son bestows Grace upon a person, human nature is not transformed but rather covered over by God's divine life. The classical example is that the bestowal of God's grace is like covering a garbage heap (that is, us) with snow (that is, grace). Again this is not the Catholic view.
From Sacred Scripture and Sacred Tradition, God's Revelation, we understand that when Adam and Eve sinned, they lost supernatural grace; they did not lose their human nature. They retained their humanity, but without grace. Our Lord's redemptive act upon the Cross freed us from sin and once more brought Divine grace into the world.This makes a big difference in terms of sexual morality and the human body. The influence of Puritanism had the effect of seeing the body as a hindrance to God's grace. One could even conclude that certain parts of the body are dirty. The Catholic Church on the other hand teaches that the human body is good, not just good but beautiful. Why? Because God created it. There isn't a problem with our bodies nor with human sexuality. The problem arises with our treatment of these matters.
We understand that sexual immorality -- sex outside of marriage, homosexual acts, self-gratification, adultery, etc. -- are wrong not because they are "dirty acts." They are wrong because they constitute a misuse or abuse of the body and God's purpose in creating it. So, a sexual sin is a sin because it's , first of all, a disobedience of God's law, and, then, consequentially it's harmful to the person. It's contrary to the purpose for which we are created.Some times a puritanical attitude was found among Catholics. But, that's what it was -- an attitude and not true Catholic teaching. It would be worthwhile to look up Blessed Pope John Paul II's Theology of the Body. Here you will get a deeper understanding -- and a beautiful one too -- of the human body and sexuality.