I agree, though people are flawed and so some people will be insecure around people who have form for a pattern of behaviour, and people in the 'biz might now have an influence on her career depending on how they feel about the situation. Some people are a lot more upset and wary about this kind of behaviour, and some people simply don't care. Of course in an ideal world no-one should care what she does apart from the spouse at home. However, she (and the men of course) have done this a few times now and have been caught by the paps, so people will talk, and the paps will always be interested in catching her out again, unfortunately. They tend to fixate on certain celebs and follow them again and again.
In all, I think Dominic is behaving tragically, and I hope Lily can let this blow over and carry on acting.
Yes, you're right, people WILL judge and look at what happened to Sienna Miller as someone mentioned up thread (she however has had a career renaissance of late so once the dust settles, things usually get forgotten/glossed over).
Dominic is indeed behaving tragically, a classic case of mid-life crisis. He has been quoted in the past advocating men having affairs and that women should overlook them (I'm paraphrasing somewhat but this was the gist). He sounds like an absolute prat behaving like a dog on heat and sticking his wick in which ever pretty, willing young thing he can find.