Is there a sexual middle class for males (monogamy)

Alot of the males are at zero. Lower class.

Then there is one female. Middle class (monogamy).

Then there is the upper class (two or more females for a male).

Does the middle class exist? Alot of countries dont have an economic middle class.

(This is complicated by the fact that sexual variety is desirable. A high number of sexual partners per lifetime as opposed to just amount of sex done.)