Besides, when one partner pushes hard for marriage (it's usually the woman, but it's the same for both genders), usually that means that s/he looking for security above all. The partner comes second.

In other words, when one greatly needs security (be it through marriage or elsewhere) the partner becomes "optional". To the point that, one day, s/he might marry someone else: meaning that marriage (and security) was their main goal, not being with the partner.

Keep this in mind when someone says "I want to marry you because I love you". Love does not require marriage, security does.

NB: There's nothing wrong in needing security; it's just that it would be honest if this was stated outright (and usually isn't).