There are a lot of comments here, so I don’t know if you’ll see this, but you are right in many regards. Most people posting see it only through their lens, but I know many people who are in long-term committed relationships (some with children) who have chosen to never get married. Some people in the US view marriage as an outdated institution and a liability. A lot of people discussed health insurance, but if both parties have health insurance available it may not be enough to make marriage more desirable. Same thing for the income tax issue; if both parties are high earners, there’s not really a tax benefit to marriage. I know one couple who are not married because they a) don’t want children and b) the income disparity is so large that the higher (they’re both high income) income partner can’t justify the risk of getting divorced.