Hi, Dr. Laura,
If I could go back in time and give my college-aged self some advice, it would be this: do not, under any circumstance, have sex before you're wearing a wedding ring on your finger. That is, reserve, and preserve, sex for marriage.
What I did not know back then is sex really does create a strong bond and unity between two people. And this holds true whether or not those two people are in fact compatible in other areas of life. In other words, two people can disagree vehemently about things having to do with religion, spirituality, money, children, lifestyle, career goals, eating habits, physical maintenance, etc. and yet they can have great sex together! (Actually, is there any such thing as not-great sex?) Sex is probably the easiest thing to agree on, especially when you're twenty-something and feeling needy or just plain horny. It's all the other stuff where disagreements can abound. What I did not know back then is that the bond that sex creates is not something that you can break or erase. It's there, and stays there. Forever. Sometimes it's so strong that you end up marrying the other person, even though, in your heart of hearts, you suspect that the two of you are not really a good match. Or if you don't end up marrying the other person, but rather end up marrying someone else, then you and your spouse have to deal with the "baggage" of the previous sexual bonds, which is a task that might well last the rest of your lives.
Either way, the pleasure you feel temporarily from pre-marital sex could result in some very unpleasant, and very permanent, repercussions.
In the end, as I told my own children when they were dating, if you want to have a happy life, please remember that faithfulness to your spouse is a virtue, a good thing, to practice. And that means being faithful to him or her not just during and after, but also BEFORE you get married. I believe that this is really important if you want to have a happy and long as in lifelong relationship with someone. Find out if you really love the person before you "make love" to him or her.
S.