I was having dinner with one of my friends and he told me that he is a millionaire. He is a fairly nerdy guy who lives with his parents. He works as an accountant but doesn't earn too much. His income is about average. However, he is the sort of person who is not very masculine, has never been attractive to women, and in his thirties he still lives with his parents. Because he lives with his parents, he pays no rent or bills and invests all of his money, and because he is unattractive, he never goes on any dates. His expenses are low and he is able to invest almost everything and become a millionaire in his thirties. For him, a lack of sex and a lack of sexual desire has lowered his expenses and allowed him to become financially successful. He is thinking of retiring early soon. He won't rule out getting a partner in the future but he does not want kids. He says not having kids will allow him to retire early.

The example of my friend seems to go against the idea that you need to be married in order to be financially successful. According to many, the benefit of marriage is that you can pool money to buy a house. Plus you get economies of scale from expenses such as heating. Supposedly living alone is very expensive.

If someone wants to be financially successful, are they better off being single? Is married or relationships bad for financial success? Many say that being single beats being coupled because of how expensive children are, but what about DINKs? What if you have a partner or share costs and achieve economies of scale but decide not to have kids eg get a vasectomy or a bisalp? Is this financially prudent?