sex before marriage

[Al-Fatihah]

I dont know if this topic has done before, i couldnt find it in these forums but i might just be bad at using the search engine.
This question is directed more at muslims.
I have had quite a lot of muslim friends in my life and not one of them, even the more religious ones have taken sex before marriage seriously, do you know why this is?
Ive known muslim guys to have non muslim girlfriends so not only commiting sex before marriage but basically putting themselves in a situation where it will happen again inevitably.
Ive had a bengali muslim girlfriend who definitely didnt care about this and in fact only ever dated white non muslims for some reason.
Even the most religious guy i know who is a muslim has heavily hinted to me that he has had sex before and he isnt married.
His opinion was that the most important rule was to honour your parents and the rest of the sins were less important, but what are your opinions?

Response: Sex is the most intimate embrace between two people. Yet if a person is used sexually, it causes the most emotional and dramatizing feeling to the person. So the law in islam to marry first before sex is to prevent the harmful act of being used sexually. In other words, having sex based on lust, and not love.

To ensure that sex is taking place out of love and not simply out of lust or using one sexually to fulfill one's own desires, then islam allows sexual relations only with the promise to agree to love and protect each other as well in writing.