Everyone seems to have different morals when it comes to relationships; some are monagamous, others are swingers/polygamous, some of us would date a friend's ex, others wouldn't, some people believe that marriage is crucial for child rearing; others not so much!
I for example would never knowingly have an affair with a married man but for other women the desire might outwiegh the moral implications. I am ashamed to admit that I once fell in love with a man who had a girl friend and I plotted to steal him. My desire for him totally outwieghed my shame and empathy for her. He was a big story in my life. If he was married I would have left it. As it happened they split up of other factors and he wasn't interested in me anyway.
I wouldn't ever steal a mate's friend and normally suppress any attraction I may have towards their partners. For a faceless girlfriend whom i have no loyalties towards I am more ruthless.
So do morals play a huge part in our relationships or does sex generally win? Do we suppress our sexuality too much or not enough? Just interested . Sorry if a bit deep.