Just 37% of U.K. adults say they would immediately step in to help their partner out of debt troubles, according to a survey conducted by asset manager Fidelity International.
The numbers fall even further if the situation happened repeatedly, with just 21% of women and 16% of men saying that they would help their partner out but only once.
In neither sex did a majority of respondents think that the reason for falling into debt would affect a decision to bail out a partner.
Just two-fifths (38%) of women said they would want to know why their partner fell into debt before stepping in. An even smaller proportion of men (30%) said they would need to know the details.
The poll of 2,000 U.K. adults was conducted by the asset manager in May 2019 and all respondents had over £1,000 ($1,290) worth of investable assets.
An almost identical proportion of men (86%) and women (85%) questioned said they would rather know about their partner's debt so they could tackle the problem together.
Britons have an average £31,284 ($40,297) of personal debt, of which £1,373 is credit card debt, according to research from U.K. organization The Money Charity.
Maike Currie, Director at Fidelity International, said that while debt could be "thorny issue" for any relationship, communication is key and tackling these issues early on can prevent them from becoming an "insurmountable problem" later down the line.
She suggested starting off by distinguishing between different types of debt and paying off the most pressing first, such as high-interest borrowings like credit cards.
Currie urged couples to have an honest discussion about debt, ensuring there were "no additional financial secrets or concerns left in the closet. "
She said that although it can feel daunting to be open about finances, getting into the habit of talking about money as couple would help when times get tough.
She added that couples should avoid pointing fingers and instead work towards financial solutions together, as this would help with feeling more in control of your money.
Currie said it is also a good idea to have a sense of each other's "financial health", for instance understanding who in the couple might be the "big spender" and who prefers to save.
"Remember, everyone approaches their money differently, and you can learn a lot from each other when it comes to money management, " she said, adding that it is important to understand each other's mindsets when it comes to both short and long-term financial goals.
"Just because you've got yourselves out of the woods once, does not mean you shouldn't be careful in future," said Currie, explaining that it is vital to prepare for life's unexpected costs.
Setting aside an "emergency fund", along with a budget for the months or years ahead can be help if "bills start creeping up again."
Similarly building up a nest egg, by putting a monthly sum into a pension or personal investment fund, can prevent unnecessary borrowing in the future, she added.
A third (32%) of U.K. adults have less than £2,000 in cash savings, found U.K. financial regulator the Financial Conduct Authority from a survey of 13,000 Britons. Just 13% had £50,000 or more stashed away.
A mere 2% had a maximum of £1,999 in personal investments and 6% had £50,000 or more, according to the data.