People married for less than a year had an average Personal Wellbeing Index (PWI) score of 73.9, scraping into the bottom end of the normal range for all Australians of between 73.8 and 76.7.
By their second year, the average PWI score for married people rose to 78.4, and from there it consistently tracked at the top end or above the normal range.
The happiest married people in Australia were those who had clocked up 40 or more years together.
"The message for newly married couples is to persevere through that first frantic year and reap the rewards later," Dr Weinberg said.
Relationships Aotearoa national practice manager Cary Hayward said the same applied for New Zealanders and often stresses of setting up a home, paying for a wedding, negotiating family relationships and planning for children were just the start of the strains on couples.
Mr Hayward said there were two main points in a relationship where couples separated: around five years and about 13 years.
He said that corresponded with the research considering most couples live together before they wed.
"If people are together for a while and then get married in their third or fourth year then that would make a lot of sense," Mr Hayward said.
New Zealanders who had long-lasting marriages also tended to be the happiest.
"When people have been together for a long time they've been through those two key separation points, they've worked a whole lot of stuff out and it probably means they've got a good operating model and good levels of emotional engagement between them," Mr Hayward said.
"And then of course once the kids have gone and the financial pressures are less, they've got more time for each other."
Mt Eden counsellor Colleen Emmens said some couples faced disappointment if they expected their lives to change dramatically after they wed.
"[Some may have] a kind of magical expectation of something being different [after marriage] and they're not, they're the same," she said.
The first year of marriage could be quite hard, even for two people who have lived together before their wedding, Ms Emmens said.
She said the important key to a long and happy marriage was to work out how to resolve conflict.
"Successful couples behave in a really different way to what unsuccessful couples act," Ms Emmens said.
"My experience is that couples are okay for a while and then there's a clash or a conflict and either that's resolved or they split.
"If it's resolved they go on again that little bit longer, then you have another conflict and if they can resolve that then on they go.
"You can't help but come up against conflict."
