The old wisdom is that marriage is an institution that works when two people put the relationship first—not so anymore, says Tara Parker-Pope in The New York Times. Parker-Pope covers some interesting information from university elite who say the secret to a long-lasting love is not self-sacrificing martyrdom, actually. It’s all about “Me.”

Professorial-types from various universities have concluded that the most satisfying long-term monogamous commitments (and we’re assuming this also can be applied to those who are in the same long-term monogamies even if they’re not recognized as valid by the law) are those relationships where “sculpting” and “self-expansion” have a heavy hand—in other words, we like the relationships that our partners make our lives more interesting and help us get to where we’re going. Surprise!

“If you’re seeking self-growth and obtain it from your partner, then that puts your partner in a pretty important position, and being able to help your partner’s self-expansion would be pretty pleasing to yourself,” says Dr. Gary W. Lewandowski Jr.

So it gives new meaning to the “better half” in a relationship—research also shows that people who hook up with others who have appealing traits often develop those traits themselves.

“It’s not that these couples lost themselves in the marriage; instead, they grew in it,” says Parker-Pope. “Activities, traits and behaviors that had not been part of their identity before the relationship were now an essential part of how they experienced life.”