For a person to enter into a marriage covenant with another, both must be free to do so. A previous marriage can be an impediment to a person’s freedom to marry. The Church refers to this as the impediment of Ligamen or Prior Bond.
For example: Joe (a Lutheran) marries Susan (an Anglican). It was Joe’s first marriage and Susan’s second marriage. Three years later, Joe and Susan divorce. Then, Joe meets Lucy (a Catholic). Joe and Lucy date and become engaged. When they go for PreCana, Joe discovers that the Catholic Church considers his marriage to Susan a valid, sacramental bond because they were both baptized persons. However, because Susan was previously married to someone else before marrying Joe, Susan was bound by her first marriage, and thus was unable to validly marry Joe. Joe seeks an annulment from the Church based on Susan’s prior bond. It is granted, and he becomes free to marry Lucy in the Catholic Church.
Other impediments include a Catholic priest or religious who attempts marriage without dispensation from his/her vows of celibacy and chastity ( impediment of holy orders); a Catholic attempting marriage with an unbaptized person ( disparity of cult); marrying an immediate family member ( consanguinity); and others.
Click the following link to download the Petition for Declaration of Nullity Due to Existing Prior Bond (Ligamen)