Essay.
A traditional triangle of a husband, a lover and a wife.
It is so topical theme. In fact a great number of family couples falles to pieces.
 First of all let`s find a definition of the word "betrayal". I think that it is an act of betraying someone or something. This word associates with unfaithfulness, lie, the break of breach and etc. 
  My sister thinks that unfaithfulness  is very bad, especially unfaithfulness of men, husbands. If husband betrays his wife then, he doesn`t respect his wife.In family between husband and wife perhaps there must be  even respect.
 As for me, I agree with her. A love triangle  breaks any moral spiritual values. For example, this summer I read a very interesting book " Return to Eden". The main hero  Jilly Stuart is main director  of the large company, her husband looked like  loyal, decent and honest. Perhaps she thought that he was such a good man. But  one day she was disappointed in him. She saw his unfaithfulness with her secretary. It  was so brutal and undignified from  him.
 Also, I have an example from the history  of Aldous Huxley the " Portrait". The romantic story within a traditional triangle of the old and ugly husband, the young and handsome lover  and  the young and flirtitious wife. Lady Hurtmore wanted to bargain to elope with sequins with her artist Giangolini.But Lord Hurtmore saw how his wife and young painter throw themselves ecstatically into one another`s  arms. But Lord Hurtmore forgave her. Lady Hurtmore remained  with her husband.
  In conclusion, I want to say that we should avoid love adventures, when we have a wife or a husband, a girlfriend    or a boyfriend.