One of the common complaints from those in long term, committed relationships is that sex is predictable and stale. What once burned with the passion of a thousand suns now barely resembles an ember. In fact, many in long-term relationships virtually schedule their sex. And, these couples insist, it’s always the same. So not only is the timing planned, but the sex itself is repetitive. While there is debate about how often happy couples have sex, it’s rather uncontroversial to…