Marriage is the only arrangement which satisfies the Emotional and Sexual needs of an individual in combination. Any individual who wants to enjoy the fruits of satisfying these needs (not the only ones though) together needs a marriage.
The theory sees the marriage as a unity between 2 people, without giving any significance to any external entity. Some examples of external entities are society, caste, religion, money, work, etc. etc.
Let me try to explain what I mean by different components of the theory,
Emotional Needs: Most of the individuals, have a emotional need to share happiness, sadness, thoughts, cravings, feelings etc. etc. with mates. The practical spectrum of mates is broad, it can be parents, friends, spouse, relatives, colleagues, neighbors, dog, cats, etc. Though the spectrum is broad, it is very rare that people find 100% emotional compatibility with their mates. But people have learnt to define the percentage of emotional compatibility needed for them to lead their life.
Yes I agree that, there are individuals who do not need have any emotions associated with them. In fact if we live in a "completely conscious state" of mind we will not have any emotions associated with us. This is the state of mind defined as "Sat Chit Ananda" in Indian philosophy. The individuals who have achieved this are, very rare exception individuals who are actually yogis, sadhus, rishis etc.
Sexual Needs: This is one of the the basic needs of which any living being needs to satisfy naturally. There are number ways to satisfy this need, masturbation, sex with individuals (gay, straight, lesbian) etc.
Important point to note is some of the Yogis, Sadhus etc. of the Indian society have an argument against "Sex" being a need. Since I am not knowledgeable enough why? how? they think this way, I agree and say there are exception individuals who do not have sexual need. But from the all the other general people perspective, Sex is a very important need which needs to be satisfied.
Marriage: General definition of marriage would be, "An institution where man and woman live together in a legal way". But if we leave out the specifics, and take the principle, the definition would sound like, "An institution where 2 individuals share their living". I think this is a holistic definition of marriage as an institution. As one can see this definition encapsulates different varieties of relationships like Live-In relationship, Gay/lesbian marriages, extra marital relationship etc.
Putting all these pieces together,
there are "emotional needs" of a being which can be satisfied in many ways.
there are "sexual needs" of a being which can be satisfied in many ways.
Marriage is an institution which satisfies these needs of individuals in a combined way. To put it the other way, the pleasure of combined satisfaction of these two needs is what makes an individual need marriage.
Although these are not the only needs of any individual, these needs stand on top in the need hierarchy with respect to marriage.
Unfortunately theories like this can be proved only through hypothesis, rather than based on actual data. I have tried to list some of the practical scenarios and see how it maps to the theory ,
Scenario 1: 2 individuals in marriage with dis-functional sex life - These individuals will be categorized as friends living together rather than a married couple.
Scenario 2: 2 individuals in marriage with functional sex life, but emotional disconnect - This would map to one individual having sex with a professional sex worker or an individual being subjected to rape.
Scenario 3: 2 individuals married for 3 years and divorced due to incompatibility - This would map to the scenario where there was a satisfaction of emotional and sexual needs for 3 years. But over a period of time, emotional needs of one or/and both individuals changed to irreconcilable levels.
Scenario 4: One person is married and has affair running with another individual - This person has found the emotional/sexual need satisfaction with another individual rather than a legal spouse.
Most of the scenarios I believe justifies the theory in a concrete way.
Reason for writing Conclusion:
After writing the theory, explanation, my own doubts on the article not explaining the theory in a conclusive way, reading all the comments from dear ones. I started off with an idea of changing the original article, I couldn't continue doing it. The reason is, it is an attempt to provide a structure to the relationship. Though it is a failure for now, I am satisfied with an attempt and want to cherish the attempt for future. I certainly want to re-look at this whole attempt in the future and want to provide a conclusive structure to the theory.
I thought it is good time to close the article with a conclusion with my current thoughts.
The reason/need for any relationship to happen has multiple facets to it. For example, money, love, intellectual match, emotional attachment, sex, proximity, interests, etc. The list will go on and on, and is not a easy task to list all the factors. Each one of us can see all these factors working in various proportions in our relationship with, friends, family, etc. Influence of these factors on an individual is defined by things like, upbringing, knowledge, genes, etc.
I believe, these factors can be categorized into mutually exclusive buckets and the general trend in the human thinking can be captured across these buckets.
Relating the above to the question, the reason/need for the effective working of a relationship called as marriage. All these factors still form a part of the relationship. Every individual will decide for himself/herself/itself what proportion of each factor is needed for the marriage to happen and work.
It occurred to me that, "Emotional Need" and "Sexual Need" are the important factors which makes the marriage work (Not the only ones) and hence becomes the need. And the pleasure associated with both of them is unique for marriage. The failure of the article is because, the article doesn't explain "Why" and "How" these factors are important in comparison to others. In fact article didn't even list the others. At this point in time I beleive I do not have enough logic, data, thoughts to explain how it is important for general people. My attempt would be understand those reasons clearly in the future.
But I can confidently say, these 2 factors together stands as high priority for me. These are the needs "I" need to fulfill to get into the institution of marriage successfully. And my efforts will be to find continuously improving mix of both these factors.
-- Madhukar Hebbar