Getting married by signing on a piece of paper in ROM means that
you are leagally bound by SIngapore's law so that you cannot marry
another person.
If you are buying a HDB house, you will need to get married legally
to produce the certificate.
Getting married means that you are commited to your partner
regardless of wealth or poverty etc... maybe is to give the wife a
sense of security so that if a divorce ever take place, she will be
compensated...
Think if you have a baby, you can still put down the both parents
name even if both are not married.
What I think is that if both party love and trust each other,
signing on a piece of paper doesn't mean a thing really... maybe
for your the sake of parents... but then divorce are so common
nowadays.
Cheap to get legally married but cost you a bomb to get legally
divorce.
Juz my thoughts 
