Gonna answer this in summary form:
Just in case you din realise, it has ALWAYS BEEN
THERE. Rise of people going pubs and seeking for ONS? Its
has ALWAYS BEEN THERE. 
Abandon marriage?
That's insanely stupid. What you see is only half the glass; the
idealogy of true love will ultimately lead into marriage, which
will be the classic case of 'once there, forever will be'.
The theory of sex and nature works close to one another, while the
theory of love and spirit is another altogether. Man by nature is
born to mate and provide, while woman is to nuture. Man are
'taught' by nuture to spread its seeds around, to propagate and
ensure humanity continues, while woman are 'taught' to cater and
nuture the young, also to ensure the young ones survive and
humanity continues. By nature you fark, by spirit you make love.

Example: Man patron bar. Man attracted physically or sexually to
any woman, man wants to screw her. (literally - spread the seeds
theory). Woman on the other hand, resist because woman has more to
invest (nuture nature). - This is provided external factor is not
considered to overweigh on both side. 
Love is spiritual. Probably only human could attain such level in
emotions. Marriage is the acknowledgement of your love blossoming
into something. NOW, marriage has merely became a certificate.
Physical evidence of superficial love - shotgun marriage, or for
any physical & measurable reasons (Wealth, financial and
probably career stability). This is the nature side of love.
Spiritual love needs no such conditions. 
Human's mind affects
this as well: Psychological needs (Status, looks, 'feel', etc)
conjunct with morals, values (Responsibility, religion teachings,
etc). The spiritual side: Cosmic lesson & karma. In a nutshell
of 100% - all these factors contribute into the person's attitude
towards relationship. (Subjective and differ from people to
people)
All these affects one's fate in any love relationship. If people
wants to screw around, Physics Law states that there will be an
equal opposite force (check out people who cheat on their marriage,
do you think they are truely happy?). Love cosmic lesson stated
that one comes into this world to learn something, repayin or
collecting -if it must involve sexuality - it will. (Check out the
chance of you marriaging your first love and happy-ever after is
like how fringin` impossible in today's context?) 
P.S: I type a whole list of sh|t, however I think its far too
nagging. Anyway, marriage will and should never be abolish

Cheers