Loyalty is always a sacrifice. But I don't think I'd ever call being fickle a virtue; it is perhaps what happens when being selective or discerning goes from being the virtue that it is into a vice.

Perhaps modern women are taught to be fickle, but I suspect this may have more to do with a broader Malthusian agenda than having anything to do with their best interests. Or just modern society's refusal to every accept anything as "enough." You rarely hear stories of elderly women telling people how glad they are to be alone and independent.

Part of a great relationship is finding the right partner, like choosing the right ingredients for a meal, or the right materials to build a home with, but arguably a much larger part is putting the work in to transform those raw ingredients and base materials into the art form you seek.

I think it's funny you say it's mannish, just because I've always heard being afraid of commitment referred to as a male trait...