Speaking from my perspective in the gay community, I don’t believe that we are meant to be monogamous in a physical sense. I have had countless conversations with friends over the idea of an open relationship. The overwhelming consensus was that having multiple sexual partners helped the couple to maintain a strong and healthy relationship.
Yes any couple could run the risk of separation, which to some would be their worst nightmare. However, as long as a strong, open line of communication is in effect, I believe the two parties will have a much healthier relationship.