There are certainly mortgages which only require the payment of the interest, rather than the principal: https://en.wikipedia.org/wiki/Interest-only_loan https

There are certainly mortgages which only require the payment of the interest, rather than the principal: https://en.wikipedia.org/wiki/Interest-only_loan https://en.wikipedia.org/wiki/Interest-only_loan But even with interest-only mortgages you don't pay indefinitely - either a) you switch to paying down the principal after a specific number of years or b) the loan-balance becomes due.