I came across this video while doing a search on videos about stoicism. Check it out.

http://youtu.be/dh43cVtfMYs

Summary : Sexiness = possession + freedom. A fully captured person is not sexy. Now imagine why a beta isn't sexy, He's a creature fully willing to go into the cage without a fight. A real fight in a relationship create drama and the possibility of freedom which ignites the second half of the equation. Possession + freedom = sexiness.