Some TV programmes can be quite informative ...

According to David Barash (a zoologist, Professor of Psychology of University of Washington and the co-author of a book entitled "The Myth of Monogamy"), monogamy is known to be a lifelong activity in only 1 animal species - a flatworm that lives as a parasite in the intestines of fish. He said that 2 flatworms meet while they are still adolescents, and that their bodies fuse together. By fusing together, these 2 flatworms remain true to each other forever (literally).

I think that is amazing. Hmm ... they live happily ever after. Fairytales do exist! In the flatworm species!