When it comes to getting down and dirty, couples can and do experience the occasional problem.
"It's the day where I see the most miserable couples, the most distressed couples," Dr Peggy Kleinplatz, a medicine professor at the University of Ottawa, told Big Think.
So, what's the source of their misery? Well, it's not necessarily caused by mismatched likes in beds, but a discrepancy in sexual desire.
However, she explained that compromising on this discrepancy isn't the solution to the problem.
"When one partner wants more - or less - sex than the other, compromise is not the answer," she said.
Dr Kleinplatz then explained that the roots of sexual discrepancy often stem from a couple having bad sex and not necessarily mismatched libidos.
"What looks like a problem of low sexual desire might be evidence of good judgment, perhaps even good taste," she said.
"It's rational to have low desire for undesirable sex."
She said couples should instead focus on having 'magnificent sex' and contrary to what you might think, this isn't necessarily characterised by orgasms.
According to the doctor, research has found that great sex is characterised by being totally into the moment and being fully 'in sync' with the other person.
"It's quite something to be fully embodied within, while simultaneously really in sync with, another human being," she said.
How is this achieved? The sex therapist explained that it's characterised by 'erotic intimacy, empathic communication, being authentic, vulnerability, exploring risk-taking and fun, and transcendence.'
She said that empathic communication is about more than just being able to literally communicate well, but 'being so in tune with your partner that you can practically feel in your own skin the way that your partner wants to be touched most.'
Research showed that the characteristics of magnificent sex remained the same regardless of age, sexuality or relationship type.
The therapist added that in order to master the skill of this kind of sex, couples need to devote enough time to their sex lives to get it right.
"The reality is that extraordinary lovers choose to devote time and energy to this most valued of their pursuits," she said. "That's a crucial lesson for all of us. Great lovers are made, not born."Featured Image Credit: Oleg Elkov / Lev Dolgachov / Alamy Stock Photo