If two people care about one another to the point where they want to have sex before they are married, I see nothing wrong with it.
I've been happy with my girlfriend for two months (which is not a long time, but we have known one another for years, just didn't date until recently).
Throughout the time we knew one another, we didn't do anything sexual together, we dated other people and were friends.
In late February 2012 or early March, we were drinking at a party and made out (that's it), and began actually seeing each other.
She slept over a lot at my house, and at the time we were both going through some drug issues, personally, mine was cocaine. Any cocaine user is aware of what people call "coke-d**k", so I won't say we didn't TRY having sex before we were officially together, but that "coke-d**k" made it impossible.
We both cleaned up, and also cut back a lot on our drinking, after a month of us dating we had sex one night, and it's been happening since.
There is nothing wrong with it, if two people are happy together and willing to do that sort of thing with them, then they should be allowed to by all means. It's two people becoming one, in a sense.
Nothing wrong with that.
Many people disagree, but we all look at things differently, I suppose - I've only met one person who wouldn't have sex until marriage, and that was due to strong religious belief.
There's nothing wrong with that either, all the power to them if they don't want to give up their virginity before they are one hundred percent certain that they will be spending a long time with this person.
The only time I look at sex before marriage differently, is when people are going around having sex with people all the time, every night, different people.
It all comes down, ultimately (in my opinion), to a respect thing. If you respect yourself, you won't have sex with a LOT of people, plain and simple, before marriage or after a first marriage.
If you disrespect yourself, well, you're going to do whatever you want.
It's really a complicated discussion and topic at the end of the day, but the point is... If someone is happy, let them be happy, whether it means having sex before marriage, or having sex after marriage.