After more than 25 years as a sex and intimacy disorders treatment specialist, I can tell you that, beyond issues with infidelity and sexual addiction, the primary concern expressed by both individuals and couples centers on the amount of sex they're having. Generally, these clients want to know how much sex they should be having versus how much sex they actually are having. Much of the time they fear they're not getting enough, though sometimes they worry about too much.
So what is healthy when it comes to sex? And, more importantly, what is the right amount of sex for you? Data provided by the General Social Survey, tracking American sexual behaviors since the 1970s, tells us that married couples have sex around 58 times per year. But this statistic does not consider the age of the couple, how long they've been together, physical health, unmarried long-term couples, etc. More detailed GSS data suggests younger couples have sex more often than older couples—an average of 111 times per year for duos in their 20s, declining approximately 20 percent per decade.
As for single people, GSS data says heterosexual adult males average 63 sexual encounters per year, while heterosexual adult women average 55 sex acts per year. I wonder: With whom are these heterosexual men having sexual encounters 56 through 63? And this discrepancy isn't the only reason to doubt GSS data. For instance, heterosexual men say they use condoms in 23 percent of their sexual encounters, while heterosexual women say they use condoms 16 percent of the time. So according to heterosexual men, they're using 1.6 billion condoms per year while heterosexual women say they're using 1.1 billion condoms per year. Meanwhile, fewer than 600 million condoms are actually manufactured and sold each year. So, yeah, it seems like maybe both genders tend to "round up" when asked about their sex lives (men more so than women).
My point here is that most people think they're supposed to be having more sex than they're actually having, and they believe this so thoroughly that they're willing to lie about their sex lives—even in anonymous studies like the GSS. As such, any data from any source purporting to know how often the average person has sex is likely to be wildly inaccurate, probably skewing toward higher rather than lower numbers. In other words, most people aren't having nearly as much sex as they'd like other people to think.
So what is normal, and how much sex is the right amount for you? The answer really depends on you—your values, your sex drive, your age, your health, your emotional state, the ready availability of a partner or partners, etc. At the end of the day, if you are happy with the amount of sex you're having, you're having the right amount of sex; your sex life is normal for a person with your unique life history, emotional makeup, and experience. Other people may want more or less sex than you're getting, but that's them.
If, however, you feel that you're having too much sex or not nearly enough sex, and this realization is causing you emotional distress, and if reading the above facts (or lack of facts) about sexual frequency does not alleviate this stress and anxiety, you may want to seek professional assistance. If you are having more sex than you feel comfortable with, a certified sex addiction therapist could be the right choice. If you feel painfully undersexed, almost any properly trained therapist can help you work through the issue, though you should probably seek advice from a medical doctor first as your problem could be physical (and likely treatable with medication) rather than psychological.
In short, healthy sexual frequency cuts a wide swath. And your desire for sex can be influenced by an incredible range of internal and external factors—age, physical health, relationship status, substance abuse issues, medications, stress, depression, anxiety, hormonal imbalances, etc. So there just is not a quantifiable norm when it comes to how much sex you should have. Basically it boils down to this: If you're comfortable with your sex life, then you're having the right amount of sex, and if you're not comfortable with your sex life, you might want to make changes, either with or without professional assistance.