Relationships are hard work. In Western societies, it is estimated that one in two marriages end in divorce. Other research shows that more than 30% of people find it difficult to maintain a romantic relationship.

What makes sustaining a romantic relationship so hard? New research appearing in the journal Evolutionary Psychology has an answer. A team of scientists led by Menelaos Apostolou of the University of Nicosia in Greece found that ‘fading enthusiasm,’ ‘long work hours,’ and ‘lack of personal time and space’ are the three most common problem areas that prevent people from staying together. On the flip side, they estimate that only 30% of adults find it easy to maintain long-term romantic relationships.

To arrive at this conclusion, the researchers recruited 123 Greek adults to take part in a 40-minute interview. During the interview, participants discussed various difficulties they faced in their romantic relationships. The researchers kept track of the difficulties mentioned by the participants (identifying 78 in total), which they then grouped into 12 broad themes. Finally, they ranked these themes from most prevalent to least prevalent. Here’s what they found.

The 6 most common challenges that hinder people from sustaining intimate relationships

  1. Fading enthusiasm. The top challenge has to do with the difficulty of maintaining energy and enthusiasm in a long-term relationship. Many people find long-term relationships to be tiring and they get bored quickly. They also feel that the passion and romantic love fades sooner than they might expect. Fading enthusiasm is especially problematic among people who dislike routines.
  2. Long work hours. Some have speculated that divorce rates can be predicted by the length of a spouse’s commute. This research adds credibility to this claim. Partners who spend many hours working or put their career before their relationship are, not surprisingly, less successful in maintaining romantic relationships.
  3. Lack of personal time and space. Feeling ‘suffocated’ or lacking sufficient ‘me time’ is the third most common reason why people have difficulty maintaining romantic relationships. People who feel oppressed or constrained by their relationship, or feel that their partner is constantly nagging them, will have issues sustaining their intimate relationship.
  4. Character issues. The data show that people who view themselves as quirky or selfish have difficulty sustaining long-term romantic relationships. Moreover, people who complain often to their romantic partners — perhaps reflecting a deeper character issue or insecurity — also find it difficult to sustain a long-term relationship.
  5. Clinginess. Clingy partners — that is, people who become easily dependent on others and too often put their partner’s needs before their own — also have difficulty sustaining romantic relationships. But there’s another side to it. People who try to exercise constant control over their partner, or easily become jealous of their partner, also have difficulty sustaining relationships (especially when combined with a tendency to expect too much of their partner).
  6. Bad sex. Sexual chemistry is important to the long-term success of a relationship. Couples who regularly disagree about the quality and frequency of sexual intimacy will find it difficult to maintain a long-term relationship.

Other factors that pose challenges are ‘infidelity and abuse,’ ‘children,’ ‘lack of effort,’ ‘social circle issues,’ ‘not being monogamous,’ and ‘behavioral issues.’

The researchers note that the importance of each of these themes depends on a partner’s gender. For instance, ‘character issues’ is the most common problem area among women while ‘fading enthusiasm’ is most prevalent among men.

The authors believe that many of these problems are compounded by the modern way of life. They write, “The mismatch between ancestral and modern conditions is likely to account for many of the factors that have emerged here. In more detail, in the ancestral context, enthusiasm and intense romantic feelings would motivate people to start a relationship, and they are expected to reside as the relationship progresses. In a pre-industrial context, the support, protection and subsistence benefits would take over, providing the incentive to people to keep the relationship. The absence of these factors in the post-industrial context, makes the fading away of enthusiasm and romantic feelings impairing for keeping a relationship, as people lose the incentive to do so.”