According to some estimates, almost 50 percent of all marriages in the United States will end in divorce or separation. But what exactly makes sustaining a romantic relationship so hard?

Well, in 2020, 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. However, if it offers you some reassurance, they also think that only 30% of adults find it easy to maintain long-term romantic relationships.

When it comes to the top challenge (fading enthusiasm, it can be explained by the fact that many people find long-term relationships to be tiring and they get bored quickly. They also sometimes realize that the passion and romantic love fades sooner than they might've expected. Fading enthusiasm is especially problematic among people who dislike routines.

Long work hours is one of those factors that might seem a little bit surprising at first but later sound really logical. In fact, some have already speculated that divorce rates can be predicted by the length of a spouse's commute. This research adds credibility to this notion — partners who spend many hours working or prioritize their career over their relationship are, not surprisingly, less involved and less successful in the latter.

Feeling suffocated or lacking sufficient me time is the third most common reason why people have difficulty maintaining romantic relationships. Those who feel constrained by their commitment, or (whether or not it's justified) feel that their partner is constantly nagging them, will have issues working on and sustaining it.

The publication said that other common problems were character issues, clinginess, and bad sex.

But coming back to what we briefly mentioned in the intro of this publication, it's important that no gender is the bad one. Just the individuals. Dr. Kristie Overstreet, a clinical sexologist and psychotherapist, highlighted that men face their own unique set of relationship issues—and a lot of them have to do with the way guys are raised. (Keep in mind that these differences are not relegated to just men in heterosexual relationships; they apply to all men in every kind of relationship.)

Fear of rejection, hiding depression, anxiety, and other mental health issues, pressure to be the financial provider, and performance anxiety around sex are just some of the things that men frequently worry about in relationships.

"Men are taught from a young age to not talk about their problems or struggles. Men aren't allowed to show or express emotions," Overstreet told Men's Health. This can actually be the root cause of many romantic conflicts. After all, managing emotions and communication is vital for every couple.