Lawyers have dubbed January 8 "Divorce Day" because of the spike in couples considering ending their marriage after the festive period.
Relationship experts blame the stress of trying to stage a perfect "chocolate box" Christmas when two people are no longer happy together.
Relate, one of the UK's biggest relationship charities, sees a peak in calls in January as issues within a marriage or a long-term relationship come to a head over Christmas.
In January 2017, Relate received a 24% increase in calls to their helpline compared with the average month, and councillors expect to see a similar peak this year.
Family lawyer Charlotte Leyshon, founder of Cardiff-based firm Lux, said she and her colleagues usually see a surge in divorce inquiries when they return to work in January.
She once received a call on Christmas Day after a wife discovered a receipt for a diamond Rolex that was never placed under the family tree, and was instead intended for her husband's mistress.
Recent data from the Office for National Statistics revealed there was a 5% increase in divorce petitions submitted to courts in 2016 compared with the previous year.
Overall, 42% of marriages now end in divorce, with the average marriage now lasting 12 years.
Ms Leyshon said it was also normal to receive extra calls and emails from people already going through divorce proceedings.
"It's perfectly usual for me to receive emails and calls from clients on Christmas Day because their former husband, wife or partner has not handed over the children for their share of Christmas Day," she said.
Relate's chief executive, Chris Sherwood said: "The reality is that many of the calls we receive in January are from couples who are already at crisis point after existing relationship tensions have come to a head over Christmas.
"With one in five people in the UK in a 'distressed relationship', we'd urge anyone who isn't getting on with their partner to seek support as early as possible.
"Contacting Relate is a positive step - we can help people in all sorts of situations to work out what's next for their relationships."
According to Relate's research, one in 10 divorcees said they could have saved their relationship if they'd had the right support.
One in five said their divorce would have been easier to deal with if they'd had more advice and emotional support.
Mr Sherwood said: "Whilst divorce isn't a decision which people tend to take lightly, we'd urge people to consider counselling before signing on the dotted line.
"Counselling can help couples to improve communication, increasing their chances of staying together but equally it can help the couple to make the decision to go their separate ways if that's what's best for them."