This is a rich, multi-dimensional topic. Let me give you a thorough, structured response covering all your questions.

📊 1. The Reality of Declining Marriage — What the Data Says
The decline is real and well-documented, but nuanced across regions.
Across 35 OECD countries, marriage rates declined by 25% on average over recent decades. In 1990, most OECD countries had a marriage rate of 5–7 marriages per 1,000 people, but by 2022, most had fallen to 3–5 per 1,000. 
Globally, the share of women who are married or in a union dropped from 69% in 1970 to 64% in 2024 — a real but relatively modest shift over five decades. The changes were more pronounced in Europe, North America, and Africa, and less so in Asia and South America. 
China is a striking example: after nine consecutive years of declining marriages from 2013 to 2022, it saw a brief 2023 rebound, but 2024 brought a 20.5% year-on-year drop, hitting the lowest marriage figure since 1980. Experts point to shifting attitudes, rising individualism, higher education levels, and financial pressures as key drivers. 
Why are people delaying or avoiding marriage?
The main drivers globally are: rising cost of housing and living, increased women’s economic independence, growing cultural emphasis on individualism, later completion of education, and in secular societies — the normalization of cohabitation as an alternative.

🧠 2. Do Married People Feel More Secure and Happy?
The data here is remarkably consistent and powerful — yes, marriage is a strong predictor of wellbeing.
Marriage researcher Brad Wilcox notes that “being married is the most important differentiator” of happiness, with a 30-percentage point happy-unhappy gap over the unmarried. Nearly 60% of married fathers report their lives are meaningful “most of the time,” compared to only 38% of single childless peers. 
Over a 14-year Gallup survey of more than 2.5 million US adults, married people consistently reported happiness levels 12–24% higher than their unmarried counterparts, depending on the year. 
Married people are approximately 16% more likely than unmarried people to describe their mental health as “excellent” or “very good” across every level of education and across all racial groups studied. 
A 2024 examination across seven diverse countries found that unmarried individuals had a higher risk of depressive symptoms than their married counterparts in every country studied. 
Even more striking: a married adult without a high school diploma reports higher life satisfaction on average than an unmarried adult with a graduate degree, after adjusting for gender, race, and age. 

🌍 3. Children Born Outside Marriage — Global Trends
Of the world’s approximately 140 million births annually, about 15% occur outside of wedlock. However, this global average masks enormous regional variation. In around 25 countries — including China, India, and most of North Africa and Western/Southern Asia — births outside marriage are less than 1% of all births, carrying strong social disapproval, penalties, and stigma for both parents and child. In striking contrast, in about 25 countries — mostly Latin American nations like Brazil, Colombia, Mexico, and Jamaica — over 60% of births occur outside marriage. 
In England and Wales, over half of children are now born to unmarried parents — a historic milestone. Historically, laws to deter illegitimacy existed from at least the early medieval period, rooted in Christian beliefs that sex outside marriage was sinful, combined with the need to protect property inheritance from father to child. 
Countries like Japan (2.4%), South Korea (4.7%), and Turkey (3.1%) remain at extremely low rates of non-marital births, where marriage remains closely linked to childbearing due to cultural, religious, and legal frameworks. Social stigma and limited support for single parents further discourage it. 

🕌🕍✝️🕉️ 4. What Faiths Say About Sex/Children Outside Marriage
All major world faiths without exception discourage or prohibit sexual relations outside marriage, and none encourage having children outside the marital covenant:
∙ Islam strictly prohibits zina (fornication/adultery). Marriage (Nikah) is described as half of one’s deen. Children born outside marriage face significant questions of lineage (nasab) under Islamic jurisprudence, as paternity and inheritance are tied to the valid marriage contract.
∙ Christianity across all denominations teaches that sexual relations belong within marriage. The Catholic Church considers marriage a sacrament and explicitly forbids sex outside it.
∙ Hinduism views marriage (Vivaha) as a sacred samskara. It is considered an essential stage in life, particularly within the Grihastha (householder) stage.  Extramarital relations violate dharmic duties.
∙ Judaism forbids fornication (zenut) through Halacha. Marriage is the only sanctioned context for intimate relations and family formation.
∙ Buddhism — while it does not formalize marriage as a sacrament — teaches the precept of avoiding sexual misconduct, which encompasses irresponsible or harmful sexual behavior outside committed relationships.

👶 5. Are Children of Unmarried Parents Given Equal Respect? Property Rights Across Faiths
Legally: Many countries now constitutionally protect the equality of children born outside marriage. The European Convention on the Legal Status of Children Born out of Wedlock came into force in 1978, requiring ratifying states to ensure equal legal rights. In later years, inheritance rights of children born outside marriage have broadly improved across Western legal systems. 
Socially: Despite legal equality in many countries, social stigma persists widely, especially in traditional communities. In many societies, pregnancy outside marriage is still considered shameful, and in some cases girls are even forced to marry just to spare families the stigma associated with unmarried pregnancy. 
By faith tradition:
∙ Islam: A child born outside marriage is still entitled to care and provision from the mother, but classical Islamic jurisprudence does not assign paternity (nasab) to the biological father unless he was the legal husband. This affects inheritance rights and the child’s full social standing in observant communities. The child is not blamed morally, but the institutional consequences are real.
∙ Christianity (Catholicism): Historically treated “illegitimate” children as having diminished rights. Modern Church teaching emphasizes human dignity for all children, but historically the stigma was severe.
∙ Hinduism: Traditionally, children born outside marriage (called apadhvamsha or dasi-putra in ancient texts) had limited inheritance rights and lower caste status. Modern Hindu law under the Hindu Marriage Act recognizes legitimate inheritance rights more broadly.
∙ Judaism: A child of an adulterous union is technically a mamzer under traditional Halacha — a status that significantly restricts marriage options within the observant community for that individual, even affecting subsequent generations. This is one of the most serious social stigmas in traditional Jewish law.
∙ Buddhism: No specific doctrine of “illegitimacy.” The focus is on the child’s welfare and the ethical responsibility of parents.

💔 6. How Are Divorced People Treated Socially?
This varies enormously by culture and tradition:
∙ In secular Western societies, divorce carries little lasting social stigma today. Divorced people date, remarry, and maintain full social standing.
∙ In South Asian Muslim, Hindu, and traditional Christian communities, divorced women in particular often face reduced social standing, difficulty in remarriage, and social scrutiny — far more than divorced men. The “double standard” is well-documented globally.
∙ In Arab and many Muslim-majority societies, while divorce is legally permissible, a divorced woman may face reduced marriageability and social suspicion, especially if she initiated the divorce.
∙ In East Asian societies (Japan, Korea, China), divorce still carries considerable stigma, particularly for women, though it is increasing rapidly.
Religious interpretations of divorce can lead to stigmatization and ostracization of individuals who choose to divorce, which can lead to a breakdown in social cohesion as communities become divided and judgmental. 

📿 7. How Different Faiths View Divorce
Islam:
Islam acknowledges that while marriage is favored, divorce (talaq) is permissible when necessary. The Quran provides clear guidelines including waiting periods (iddah), financial maintenance, and attempts at reconciliation.  The Prophet ﷺ said: “The most detestable of lawful things before Allah is divorce.” It is halal but discouraged — the last resort after sincere reconciliation efforts fail. Islam also provides the woman the right to khul’ (to initiate divorce by returning the mahr), and the husband’s obligation of maintenance (nafaqa) during iddah is mandatory.
Christianity:
Generally, Christianity views marriage as a lifelong commitment and divorce is typically frowned upon. Roman Catholicism considers marriage a sacrament and does not allow remarriage after divorce unless a formal annulment is granted. Protestant denominations permit divorce if the marriage is beyond repair, and also support remarriage in the church. Orthodox Christianity permits divorce and remarriage under stringent conditions. 
Hinduism:
Hinduism regards marriage as a sacrament (samskara) rather than a contract, with traditional emphasis on lifelong unity. However, the Hindu Marriage Act of 1955 permits divorce under conditions such as cruelty, desertion, mutual consent, and adultery. Yet in many orthodox families, divorce still carries heavy stigma — women especially may face social exclusion. 
Judaism:
Religious divorces in Orthodox Judaism must go through rabbinical court processes before a “get” (a religious divorce document) is issued.  Without the get, a Jewish woman remains bound religiously (an agunah, or “chained woman”) even if civilly divorced — a serious social and legal problem in some communities.
Buddhism:
Since Buddhism doesn’t have strict tenets about marriage, divorce is allowed and unrestricted. It may actually be recommended if an unhappy marriage causes stress or suffering. 

Summary Perspective
The data presents a striking paradox: as marriage rates decline, evidence for its benefits only grows stronger. Every major faith tradition — across theology, culture, and law — constructed marriage as the foundational institution precisely because human experience consistently shows that committed, covenanted unions produce better outcomes for individuals, children, and societies. The data on happiness, mental health, children’s welfare, and social cohesion all confirm what the fitrah (natural human disposition) and all prophetic traditions have long affirmed.
The modern turn away from marriage is less a triumph of freedom and more a reflection of economic pressure, spiritual emptiness, and cultural dismantling of institutions that once carried the weight of human flourishing.