Is a threesome ever a good idea in a relationship?

The circumstances need to be right for a threesome, and in truth there are a lot of variables when three people are involved. At relationship charity Relate, we do hear about situations where threesomes have gone wrong, and it is worth noting that this is not uncommon.  But there are also people in strong, happy relationships who have introduced another person to the bedroom and it hasn’t been a problem. Some people have it on their bucket list and just want to try it once, whereas to others it becomes more of a lifestyle choice where they regularly hook up with other people.