Considering marriage was a legal and social contract before religion took it over I see no connection between sex and marriage. I do not think sex is sacred either and do not believe that it should be reserved for any particular event or that virginity should somehow be prized; the only difference between a virgin and a non virgin is literally that one of them has had sex, you do not become a different person and it doesn't act as some gateway into slutty behaviour. The idea that sex should be saved for marriage is ridiculous, a marriage can exist without sex and should be based on something that transcends lust and can bring two people closer than any physical contact could. Personally if I were to get into a relationship with someone my own age (22) then I would expect them to have some experience (although if they didn't it wouldn't be a problem) and would prefer it if he/she knew what they were doing.
Sex (in all of its forms) is obviously a completely normal and way of either showing affection or having some fun. It feels good and it's enjoyable and it seems ridiculous to cloud a biological process with a religion that isn't natural and is man made and looks to opinion rather than fact. It seems silly to place rules on sex between two consenting people, it's like trying to control the weather, or telling the grass not to grow.