This is an excerpt from one of Barabara Marciniaks books ; I truly recommend all of her books as they are all great sources of knowledge:.
If you are in a Pleiadian civilization, the expression of love and sexuality at that moment is literally so complete and balanced and whole that there is no need to attach themselves to the other person and drag them through eternity. Because they have so many of these whole and complete interactions, they feel secure - in themselves and in their expression of their sexuality. There are also married groups, which you have here on your world called "polyfidelity," which is simply taking the monogamy idea and expanding it so instead of two people, there are three or more. These marriage units are very loving, very connected, very committed to each other. This does not necessarily mean that they never live with one person or never have a type of marriage relationship with one person; many of them do. The difference is that they recognize immediately when it's time to move into something else. When you on your planet are in a relationship and feel that it's time to leave the relationship and you go and tell your mate, the mate quite often will be very hurt, will attempt to latch on to you, will show a lot of pain, etc. On your planet, however, 100% of the time when one of you feels the relationship is changed, both of you have. It's just that one person may not be recognizing it, or may be living in their own type of creation and cannot see what's really happening. This is changing now, as all of you are committing yourselves to your own personal growth.