"There frequently lies a corruption of the idea and the experience of freedom, conceived not as a capacity for realizing the truth of God's plan for marriage and the family"
Pope John Paul II, Familiaris Consortio
From the Catechism of the Catholic Church:
1650 Today there are numerous Catholics in many countries who have recourse to civil divorce and contract new civil unions. In fidelity to the words of Jesus Christ - "Whoever divorces his wife and marries another, commits adultery against her; and if she divorces her husband and marries another, she commits adultery" the Church maintains that a new union cannot be recognized as valid, if the first marriage was. If the divorced are remarried civilly, they find themselves in a situation that objectively contravenes God's law. Consequently, they cannot receive Eucharistic communion as long as this situation persists. For the same reason, they cannot exercise certain ecclesial responsibilities. Reconciliation through the sacrament of Penance can be granted only to those who have repented for having violated the sign of the covenant and of fidelity to Christ, and who are committed to living in complete continence.