Millennial couples are more likely to live together, with 65%, versus 37% of Gen Z couples.
More than half of couples, 54%, said finances were part of their decision to move in together.
Half of couples don't split the mortgage or rent equally, and 39% do not split pet costs equally, the survey found.
Experts say the survey results underscore that when it comes to sharing expenses, equal isn't always equitable, or fair.
"I think it's almost not fair to split finances 50-50 without taking into account your partner's financial situation," said Daigle, who is also a member of the CNBC Financial Advisor Council.
Persons:
Gen Z, Michael Kraus, Cathy Curtis, Curtis, Sophia Bera Daigle, Daigle, Carli Blau, Blau, Kraus, Couples
Organizations:
Istock, Getty, of Psychology, Finance, Yale University, Curtis Financial, CNBC, Society
Locations:
U.S, Oakland , California, Austin , Texas, New York