sri lankan men marry for sex...nothing else. if we had a more liberal culture not much men will marry. once they get the sex experience from GF they will realise that there is nothing much to get married.
even guys who have GF have told me that once they are in a sexual relationship after about 6 months it gets really boring and you want to move on. the only thing is that both of you will in a separate lives so not much of an issue.