Provided the situation is not too destructive, children fare better when their parents remain together even in less than perfect marriages. From a Christian perspective, such efforts matter enormously and the graces which result can assist all family members on their road to holiness.
In cases where there has been infidelity, or where love and communication have declined, forgiveness and reconciliation should be the first priority. The grace of the sacrament of Reconciliation should be sought as the way to rebuild the relationship to a new and stronger level. Separation should be considered as a last resort after all other efforts at reconciliation have proved unsuccessful.
If there is continuing domestic abuse, or physical or emotional violence, it is important that individuals protect themselves and their children, by separating if necessary.
Sometimes it will be appropriate to take the further step of obtaining a civil divorce, so as to finalise custody, property and maintenance arrangements, and to seek clarification from the Church’s marriage tribunal of the validity of the marriage.
It is important that Catholics recognise that, in itself, divorce is not a sin.