A: First, “Marriage possesses the favor of law; therefore, in case of doubt, the validity of a marriage must be upheld until the contrary is proven.” (Canon 1060) The Church always assumes a marriage cannot be annulled until proven otherwise.
The required conditions of the Church for a valid marriage are: that the couple be of age (minors require the approval of their parents), be married before the legitimate representative of the church (this is necessary for all Catholics), and are free to enter into the sacrament of marriage.
“For Catholics there is no marriage without a church wedding. In that ceremony Christ enters into a covenant with the husband and wife and generously endows the couple with graces and gifts.” (YOUcat #425) For Catholics, marriage is a sacrament, not a contract. This is why the marriages of Catholics who get married outside of the Church are not recognized, however, there are ways to have your marriage recognized by the Church by means of a convalidation (which is commonly known as “having your marriage blessed”). This presumes there are no impediments to the marriage such as a previous marriage or some other reason.
The majority of annulment cases examine whether either party was truly “free to enter into the sacrament of marriage.” This is not an easy area to investigate which is why the annulment process can take over a year to complete with no guarantee of success. If it is determined that by reason of a lack of maturity, coercion, or lack of understanding a person(s) did not or could not really make a life-long commitment at the time of their marriage it is deemed invalid thus giving the Church the ability to annul the marriage declaring the person free to re-marry. Such a declaration does not render any children as illegitimate or deny what was shared by the couple during their married life together.
Therefore, the annulment process is really the Church’s attempt to bend over backwards to both preserve our belief in the permanency of marriage as well as to reach out to people who have experienced painful marriage celebrations.