FRIDAY, July 29 (HealthDay News) -- A growing number of young American adults are engaging in what's called "stayover relationships," in which they spend three or more nights together each week while still having the option of going to their own homes, a new study shows.

"Instead of following a clear path from courtship to marriage, individuals are choosing to engage in romantic ties on their own terms without the guidance of social norms," study author Tyler Jamison, a doctoral candidate in the human development and family studies department at the University of Missouri, said in a university news release.

"There is a gap between the teen years and adulthood during which we don't know much about the dating behaviors of young adults. Stayovers are the unique answer to what emerging adults are doing in their relationships," she added.

There are a number of reasons for this growing trend in stayover relationships, said Jamison, who interviewed college-aged adults in committed, exclusive relationships.

"As soon as couples live together, it becomes more difficult to break up," she explained. "At that point, they have probably signed a lease, bought a couch and acquired a dog, making it harder to disentangle their lives should they break up. Staying over doesn't present those entanglements."

The couples in the study with stayover routines were content in their relationships, but didn't necessarily plan to move in together or get married.

"Many college-aged adults are students who will soon be facing a transition point in their lives," Jamison said. "Most students do not have a definite plan for where they will live or work after graduation, and stayovers are a way for couples to have comfort and convenience without the commitment of living together or having long-term plans."

The study appears in the current issue of the Journal of Social and Personal Relationships.

More information

The National Marriage Project at the University of Virginia has more on relationship trends in the United States.