marriage is a term applied to whatever is acceptable within a culture/society to define relationships and rules of inheritance.

Since human males do not have the ability to carry an embryo/fetus to term, a major focus was placed upon control of females in order to identify/confirm paternity.

As for forms of marriage... in the Judeo-christian tradition we have references to multiple wives, harems and assorted concubines. All of whom seem to be regarded as possessions of the male figure.

And shall we investigate common law marriages?

It's a term with multiple meanings and nothing more, except in relation to emotions and legal definitions.