The affairs are not motive, but it does goes to character. There could be some people that see if he had affairs, then he murdered his family. But one does not equal the other. Bias by some jurors as a man having one or more affairs has to do with the value system or morals. We all know how people feel about others that have had affairs. So yes, it was correct to over turn the vedict, because the affairs were not proven to go to motive, nor used as motive.
Now with the next one, I don't know. It may be similiar, but hoping that the verdict is upheld.