Doesn't Sex first time make you husband and wife and if with another person fornication?

[stacie]

I was thinking in the old testament it says when you have sex with someone that person you are husband and wife too and if you have sex with another person besides that person you are doing and fornication.think about it MARRIAGE is a man made creation.technically a ring and paper doesn't determine that.when you have sex if you get pregnant "you weren't married"then why would God bless you with a child when children are supposed to be for husband and wife or RAPED which is still sex but why would God make them pregnant