The thing is, they aren't love triangles. They're exploitation triangles, using triangles, greed triangles, lie triangles, but not love triangles.
Don't get me wrong, people can stumble into triangulations, into affairs, when they don't have the strength to resist an attraction - but in cases like that, if they're really looking for healthy love, they'll soon realize this can't stay as it is, and they break the triangle one way or an other. They make a choice.
When there's clearly no intention of ever making a choice - then it's a triangle for sure, but it isn't about love.
I watched my closest friend in college waste her love and goodness on a married man for a decade. When he finally did divorce his wife, he dropped my friend like a hot rock, and took up with a third woman he'd been playing along for several years. My friend was devastated. What I remember most throughout our friendship is her loneliness on the big holidays - because those were always spent with the wife and kid, and she was left to fend for herself - and her tears, her feelings of self-betrayal - so many nights I sat up late letting her cry it out over coffee, wishing I had some way to tell her that I was sure he was using her, knowing she couldn't hear it.
It's made me very gruff about affairs, I'm afraid. I sound unsympathetic, but I'm not - I just still see the tearstreaked face of my friend, still see her lonely Christmas Eves, her empty Valentine's days - see her throwing away the best years of her young life on a 'playa' who never loved her, never.
My friend and I lost touch. After the jerk dumped her, she felt so ashamed of having wasted a decade on him that she couldn't bear to be around people like me who knew and supported her through the worst of it. I accepted that, and I hope that she has healed and found someone who really values her.
But I'm very gruff and blunt about affairs. For this I apologize, because I'm sure it has stung where it was never intended to.