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To me, the continuing problem is the societal insistence that sexual monogamy is our natural state. Or rather, conceding that it is not, it is the view as expressed by Katherine Hepburn's character in "The African Queen": "Nature, Mr. Allnut, is what we are in this world to rise above."
That may be true as to anger and violence, but not lovemaking. Then it's a question of what you are emotionally comfortable with. The automatic condemnation of nonmonogamous sex practices is bigoted and intolerant. The Polynesians were getting along just fine with relaxed sexual practices until we Christianized them out of them (with mixed success).
Let each find his or her bliss. And let those, including lovers who can't handle it, go on their way.