David Hella came back because she was supposed to. I don't think if she had knowledge of his affair that it would have made her not return to Paris, especially if she knew it was with another man. Women are most often threatened by other women, not as much so by men. At least that's what I think. A woman can compete with another woman, but not so with another man. Besides, it's not that uncommon to find a male-female relationship where one partner or even both have a same sex lover on the side. These arrangements can span a lifetime. I don't think one would work for me, but I understand how they can happen.