Well I've been with my boyfriend of 5 years, we live together etc and I have no regrets thus far. And even if we break up in a messy way, I would still have no regrets, because it was a good relationship with someone and expressed my love for them emotionally, physically etc.
I don't need marriage to validate my love for someone. My boyfriend's parents (who are still together) are still unmarried. They have had three children and are very happy. I realise you may have religious reasons, but for those who don't, no marriage does not mean that you are any less in love or committed to a person.
It's fine that you personally believe in sex after marriage. I'm just dumbfounded with the fact that you don't understand sex before it.