IMO Ronaldo is not attractive because of his attitude, and on pitch theatrics, which show his considerable lack of respect for others, or for playing a game fairly.
Therefore, it was not much of a suprise to see that he had hooked up with Paris. Obviously, I cannot comment on her actual personality, as I don't know her personally, but she comes across as a person with very similar values and attitude to Ronaldo.
So, while I appreciate that he may be an ultimate crush in terms of eye candy, lets appreciate that for what it is, simply someone to look at and appreciate for their looks. In terms of him as a person, I think it was pretty clear the type of person that he is through the way he acts, and as such I think it's unfair to effectively 'blame' Paris for something that is ultimately attributable to his character and was pretty clear before these actions.
Just my opinion.