By the end of next month two of the UK's most popular dating websites for extra-marital affairs will boast a million members each.

Kate (not her real name) has been in a long-term relationship for 20 years, but started using one of the websites when "things weren't going well" in her relationship.

The websites allow people who are already in relationships to arrange dates or initiate affairs with someone new.

Kate says her partner has "no idea" that she is meeting other men, but that "what you don't know doesn't hurt you".

This clip is originally from 5 live Daily on Monday 23 February 2015.