One in five debt advisers says they often encounter clients whose partner has forced them to take out credit or used their credit card without asking, a report has found.
Some 20% of advisers said this is the case, according to relationship support charity Relate, which launched the wide-ranging report in Parliament on Tuesday.
Financial abuse - when one person controls another's access to money - was highlighted as one way in which people's relationships can lead to debt problems.
Nearly three in 10 (29%) debt advisers often deal with clients whose partner has used all their joint resources.
The report, titled In Too Deep: An Investigation Into Debt And Relationships, also found that 19% of debt advisers often encounter clients whose partner controls access to their income, benefits, bank account or savings and 22% often encounter clients with partners who force them to pay the entirety of their joint bills.
Chris Sherwood, chief executive at Relate, said: "Our research reveals the worrying prevalence of financial abuse in relationships.
"Financial abuse, such as withholding money and controlling access to bank cards or accounts can leave a partner feeling isolated and without a say in their relationship, which can seriously affect a person's self-esteem.
"The other person may feel trapped, resentful or feel the behaviour is normal if the abuse has been taking place for a long time.
"Their partner may have convinced them that the way money is being managed is best for their relationship.
"Financial abuse can also be a significant reason for debt itself, for example if one person has been spending large amounts of joint money without talking about it."
Debt advisers told Relate that clients are not always aware of the financial association that can be created on someone's credit report by applying for credit jointly with another person.
This association can remain even after a relationship breakdown, unless the person informs credit reference agencies that it needs to be removed.
The report also found that removing a financial association can be a complex issue, if former partners have to work out money owed to each other and pay off an existing loan before applying for a new one, for example.
More than half (58%) of debt advisers often encounter clients who have had problems accessing credit due to a financial association.
Debt advisers were found to be supportive of the idea of receiving more training in identifying financial abuse and helping financial capability for couples, such as increasing both partners' financial literacy and encouraging joint decision-making.
Mr Sherwood said: "The debt advisers and relationship counsellors we spoke to want more training around identifying financial abuse and we'll be looking at ways our sectors can work together to provide more joined-up support around debt and relationships."
He suggested those with a controlling partner should try to find out the extent of how much has been spent and the level of debt.
He said: "Consider speaking to a financial expert about the practical side of things and if you feel it would be appropriate for your situation you may want to consider relationship counselling either together or individually.
"As with most relationship issues, we'd always recommend talking openly and honestly about what's happening.
"However, (if) you feel you'd be compromising your safety by doing this, we'd suggest contacting the National Domestic Violence Helpline for free on 0808 2000 247."
More than 4,000 people across Britain and 360 debt advisers were surveyed for the report, which is sponsored by Provident Financial.
The report's external advisory group included Christians Against Poverty, Citizens Advice, Early Intervention Foundation, the Joseph Rowntree Foundation, the Money Advice Service, the Money Advice Trust, StepChange Debt Charity and Toynbee Hall.