Marriage is a compound complex man-woman-intimate – spousal, conjugal, parental – interrelationship that has relevance to practically all aspects of human life from the physiological to the mental, from the affective to the volitional, from the domestic to the communitarian, from temporal to spiritual realities. So it is too that contrary to common perception, it is not that easy to get really and truly married, i.e., to contract marriage validly or effectively as stipulated by natural and positive laws.
Yes, to merely contract marriage is rather easy and fun as well. But to enter into a valid marriage – realistic, effective, binding – is definitely neither that simple nor carefree. Among the many other validating demands for marriage intents and purposes, the required sound socio-affective plus healthy mental personality constitution on the part of both the man and the woman are imperative. Otherwise, a de facto marriage is de jure null and void from its very start. Yes. Marriage was in fact held. But the said marriage is in effect invalid from the time it was thus held.
In other words, considering the manifold yet complementary signal demands of marriage, much is understandably required from the man and the woman concerned to become not only blissfully but also validly or effectively married. In other words, marriage is not simply a man and a woman wanting to become coupled individuals, conjugal partners ultimately viewed for them to eventually bring about a domestic community which they build, they love and care for with continuous affection, understanding and support.
In other words, marriage is definitely and practically much more than a man and a woman falling in love, wearing wedding clothes, marching to the altar, saying “I Do!” before the solemnizing minister and thereafter hurrying to leave in order to presence their wedding party, to cut the wedding cake, etc., etc. All the forgoing are rather easy to accomplish and pleasant to comply with. But very much more than the wedding preparations and rituals is the pivotal question if both the parties – the man and the woman concerned – are qualified to enter into a valid marriage union, viz., if they are both without simply free from any invalidating Impediment but likewise free from any nullifying personality feature rendering marriage void ab initio.
So it is that Impediment means an obstruction, a hindrance, a stopple to effective or valid marriage. And if the impending marriage factor effectively renders the said marriage ab initio null and void, i.e., makes the marriage-in-fact invalid at the time itself of its celebration, there is then the existence of an invalidating reality canonically and officially called a “Diriment Impediment”. In other words, that as marriage takes into account the intrinsic nature, the essential attributions, the lasting basic obligations and inherent finalities of marriage in the realm of Civil Law, so it is that Church Law itself provides and defines what are the concrete and specifying nullifying factors of marriage any of which invalidates marriage from the very time of its de facto celebration. Let it be duly noted that in these times, there are more ab initio null and void marriages on the ground of mental impairment such as in terms of any downright Personality Disorder. As very well said: Being forewarned is being forearmed.