Sex complicates things.

Even the simplest relationships (coworkers, friends, acquaintances) can go from easy and straight-forward to messy and difficult. While the trend in recent years has been the “casual” relationship, smart men and women will steer clear of this trouble.

“Friends with benefits” sounds like a great idea to two horny people who had maintained their platonic relationship until a depressing lull lures them into each other’s beds. After the storm of feelings and the stints of awkward encounters ends, the friendship is left in shreds of rejection coated in jealousy.

To be clear — this kind of encounter is not the same as a one night stand. There are many circumstances where two people can have a brief sexual encounter and part ways with no hard feelings (and usually no real satisfaction). However, when the “casual” encounters become regular and with the same person, then the trouble begins.

First of all, the term “friends with benefits” illustrates the first sign of trouble. The lovers are already friends. That means that they already like each other enough to spend time together and get to know one another. Mix sex into the equation and the feelings only amplify. Turns out, if someone’s willing to bare their genitalia, then they’re probably willing to bare their soul.

If the person is not necessarily a friend, but a causal acquaintance with intent to stay casual, there will also inevitably be complications. The individuals are bound to talk at some point. They will get to know something about each other’s lives and little by little begin to get attached.

Then, when it’s time to pull the plug, someone is going to be faced with one of the most horrible of human emotions — rejection. It doesn’t matter if it’s by a stranger or your best friend. Rejection is virtually always painful.

In addition to the emotional reasons to avoid this train wreck, there’s simple logic to consider. Studies have shown that men and women are more satisfied with sex in a committed relationship.

According to Les Parrot, professor of psychology at Seattle Pacific U., “Numerous research studies make it very clear that the people who have the best quality and most frequent sex are married couples. That says a lot about the inadequacies of ‘casual sex.’ ”

This is not to say that everyone should hurry to run out and get married, but for those men and women hiding behind a “fear of commitment” — grow up. That excuse has been used so many times by now that it’s changed from a reason to a cop-out.

It’s pretty simple: people who are lonely and seek to fill that void with “casual sex”will fail more often than not. Maybe it will be fun for a while, but in the end someone’s going to get hurt. The people who just want sex should find someone they are actually romantically interested in and they can take “just sex” and turn it into great sex. If they don’t have time for that, then it’s a lucky thing they were blessed with a hand to take care of the job themselves.

For those looking for a month or two of satisfying no-strings-attached sex leading to a month or two of sobbing over devastation, this might just be the relationship for them. For most people however, opt out of the pain and awkwardness and find someone to date for a while.