Christianity VS. Western Society?

you know how christian people are always 'holy' or rather trying to do everything according to the bible. well i'm not laughing or teasing because i am one of those people who tries to keep myself clean most of the time and hopefully not sin against God.

well,something got me pondering. in the western society,everything is so materialistic and the people are so 'open' if you know what i mean. i of course have many ang moh friends in church and sometimes we girls just like to have a girls night out or meet up for coffee or tea or something and we share our secrets or our troubles and hopefully pray for each other and all the secrets shared are to be kept within the circle. well of course few of them have shared that they've had sex with their boyfriend or ex-boyfriends and come to think of it,if the bible tells us that premarital sex is a sin,then doesn't the western society becomes a problem? i mean because they claim to be christian,they OBEY all the rules or commandments that a christian are suppose to obey except this,i mean,they are so open about it and they have of course shared stories about their sex life and etc. it just makes me wonder how can christianity which is a pure religion clash with the western society now? or i should say that even the asian society is becoming more like the western society. agree?