Who gets left out, ignored, dismissed or denied when someone states that sex, good sex or real intimacy or love should, can or does only happen within the context of monogamous marriage, or when any given couple has only had one spousal sexual or romantic partner in a lifetime?

More than a few people.

• gay, lesbian or bisexual people in same-sex romantic or sexual partnerships in most parts of the world, including those with families
• people whose life or committed partnerships are platonic or affectionate friendships, same-sex or opposite-sex, not romantic or sexual marriages
• people under the legal age to marry
• those who are or who have been married and who did not or have not found all or any of those things within their marriages
• rape or incest survivors, when others or culture class rape as sex
• those who have been married and were abandoned by their spouse
• couples who are not yet married, and intend to marry but are sexual together now
• those who are married to someone who has extramarital sex or romantic partnership, or who are or have been engaging in same themselves
• those who are raped or abused by their spouses (in America alone, most statistics show that spousal rape -- which is considered a lesser crime than other rape in many states -- accounts for at least 10% of all rapes)
• those who are polyamorous, or whose families or relationships are more than two-person, even if only one of those relationships is romantic or sexual
• those who have been or are married to cultural conservatives who have had affairs, used prostitution services, are having extramarital same-sex sex, raped children, or otherwise engaged in behavior which stands quite counter to the "sanctity" of marriage
• those forced or coerced into unwanted marriage
• the more than 9 out of every 10 people who have sex before marriage, including those who say they are saving sex for marriage, have saved sex for marriage or are telling others to save sex for marriage
• the vast majority of men and women who masturbate or who have masturbated
• the vast majority of people who will have more than one romantic or sexual partner in their lifetime -- a thorough census sponsored by the CDC from 1999 to 2002 found that on average, adult men between the ages of 30 and 44 reported an average of 6-8 sexual partners in their lifetimes, and adult women an average of four. According to The Kinsey Institute, 80% of American men and 69% of American women report having more than one partner in their lifetimes to date.
• divorced people who have other relationships or remarry
• people in parts of the world or in communities who are considered "unfit" for marriage due to things like social or economic status, disability, appearance, differing religion, previous rape, caste or race (even in the United States, interracial marriage was still illegal until the late 60's)
• widows and widowers who later have other relationships, or those whose partners have died and who later have other relationships
• those with certain hereditary diseases which disqualify them from marriage
• adults with legal guardians -- such as some developmentally disabled adults -- who will not give consent for their wards to marry
• couples in some cultures who are not related, but who share the same surname
• those who identify as asexual
• couples whose citizenship status does not allow for marriage
• trans gender or intersex couples who are blocked by legal restrictions based on assigned sex, genital appearance or their particular state of transition
• people who do not want to get married for political, personal, financial, familial or other reasons

How many of those groups are you, or someone you have known, a member of? How many do you think you might be in within your lifetime? Have you ever felt real intimacy and/or had sex you enjoyed and which left you feeling good physically and emotionally while a member of any of those groups, or NOT had any of those things while married? If so, does that make you delusional? Does your reality not exist?

By the by, when restrictions like these to marriage have been protested and changed, those movements have almost always NOT come from the groups of people championing marriage, stating that it is the only right, best thing for everyone. Rather, these changes have usually been made or fought for by progressives who do not share that attitude, and protested, challenged or denied by conservatives -- such as the Defense of Marriage Act here in the United States -- who claim marriage as the only right way, the best way, the ideal we all should share.

When you look at a list like this, it's hard to ignore that in many ways, marriage is a class issue, an issue of privilege and maintaining privilege, and one plenty of people want and have always wanted to keep limited to a given class. That's obvious just by knowing the additional legal privileges and benefits married couples are often given in many countries which unmarried couples are not. It's not a wide-open door for anyone and everyone who want in, and those who champion it above all else are not ignorant to that fact. They are usually fully aware of at least some of these restrictions, and many even support or have supported some or all of them, past or present.

The term "endogamy" means that marriage is restricted to a certain group of people. That term is often applied when discussing, for instance, tribal cultures where only a member of a given tribe is allowed to marry within the tribe. But that term, in many ways, can easily be applied to marriage, full-stop: in many ways, marriage remains, nearly everywhere not big-tent, but endogamic: something only available, when it is even wanted, to certain groups, tribes or individuals.

If marriage is, as we often hear lately, what everyone should be doing or aspiring to, if it's really what some folks want for everyone and really the only right way to happiness and sexual health (even though we know that not to be true) and bliss; if the push for us to get in it is truly coming from a place of love and care, then why is "everyone" such a tiny group of people?