Bryan Martin wrote:

Marriage has nothing to do with religion. It's true that most religions
have adopted the concept of marriage and tacked on their various religious
trappings and rites and ceremonies, but the core concept of marriage is a
social convention regarding the care and raising of children. All of the
tax breaks, insurance benefits and other various benefits associated with
marriage exist for the purpose of easing the burden of raising children.

Ideally, this would have been true. If so, though, multiple marriages would
permitted. In fact, there's a fair chance that they'd be encouraged given
the greater redundancy involved in having more "parents".

[This is something of which I'm very aware when I'm flying, now that I'm a
parent myself.]

- Andrew