This is why it's important to have sex with your partner before entering into a long term commitment like marriage.
What a dumb move it would be, to marry someone without testing the waters in what will be the MOST important part of your relationship--ie, the physical connection/intimacy you will share.
The only reason religious couples that have sex before marriage feel guilty about it, is because their society has a stigma towards pre-marital sex (which was brought on by the religion). There is no rational argument you can give towards why pre-marital sex is inherently immoral...other than "oh well the bible tells me so".
I don't find premarital sinful in itself, but it's not the measure that will build a long lasting relationship. Trust me, if you've been married for any length of time, sex is not the most important thing in a marriage. If may be at first, but when kids come, bills pile up, ect.. commitment, parenting, trust, and friendship are the most important things.
I had one failed marriage and slept with I'm sure over 100 women in my life. Overall, I was great at sex, but terrible with relationships. Even when I got into lasting relationships, living together, ect..they all ended not because of bad sex, but because of not taking the time to build emotional commitment. I lacked maturity, because great sex was the first priority.
Even in relationships where sex was good, I still cheated, because a mind and heart commitment were never built over a period of time. I also lacked respect and trust for a girl that dropped drawers the first date.
When I met my wife, she had never been married and was 31. She had had a few relationships, one long and serious that was headed for marriage, but didn't make it. She had only been with just a very few men...mainly due to dating the same guy for 12 years.
We dated over a year before she would have sex. I was madly in love with her...but it was heart and mind first. She wasn't a radical. We both weren't even in church in the time. She was a model, Mrs. Winston Cup at one time, ect. She had men chasing her by the hundreds. She just viewed sex as something a man was going to have to work and wait to prove love and commitment.
She wasn't that great in bed at first, not that any sex is bad). Frankly, she lacked, compared to the wild kinky women I had been with. But I didn't judge her for that. She was what I wanted and with communication and love, two people can become great at sex, {if they don't have "hang ups.} I would have married her if she remained average with sex or even if she had decided to wait until we got married. She is great now and highly skilled and very open minded.
It also didn't take very long for her to become good. The fact is, two people learning each other become good at sex together as a team.
Having lived both sides of the fence, I would never recommend anyone demanding great sex before marriage. Finding a girl that made me take the time to build a friendship, understand commitment, I was finally able to have a lasting relationship.
Those that know me here would probably call me liberal. I don't biblically argue against premarital sex. However, I am convinced those that wait and find the right person will be happy, regardless of if the sex is good or bad at first. I also believe the marriages that will work are those that can wait until marriage or at least know they will marry.