I am personally a bit sensitive to that kind of phrasing, since when I came out about having two men in my life one person's reaction was "that's handy, if one of them dies or dumps you, you will have one left". It felt extremely offensive to me and to them, and reading pretty much the same thing is kind of a sore spot.
This being said, you can have less committed, less involved relationships, that will hurt less or differently when they end, and when you have more than one partner, one relationship ending still offers you the support of the others.
Still, I can't imagine someone would say something similar about children for instance. Ted Turner is free to describe his own relationship, but I hope it was really him doing so and not somebody else, as it was done for me.