Housing Justice was speaking after research by another charity, Shelter, showed that nearly one in three people who live with their partner think they could end up homeless if their relationship ended.
Shelter said that this would equate to 4.9 million people if the findings were projected across England.
Official statistics suggest one in six cases of homelessness are down to relationship breakdown.
Alastair Murray, from Housing Justice, told Premier: "We as a country have not been investing in housing that we need for people on lower in come for decades, it's been left to the market so house prices and private rent have risen many times more quickly than wages.
However Mr Murray said that Christian landlords can help tackle that problem: "If Christians have investments they can help in the creation of housing for people on average incomes, there are many landlords nowadays who are renting out their properties at higher rates than people can afford."
"When young couples are first getting together and getting married they're having to stay with their inlaws, certainly for some time, simply because of the cost of housing and having to save up for a deposit."
Listen to Premier's Hannah Tooley speak to Alastair Murray here: