Open relationships and celebrities

The whole Tiger Woods scandal made me wonder:

Why do so few celebrities negotiate themselves an open relationship? OK, some of them might be in love with someone special who doesn't agree to it, but what's up with the rest?

I know that open relationships are not for everyone, of course. I also know that monogamy is so much of an assumption in our culture that even most of the people who'd prefer an open relationship probably do not raise the subject with their partners.

Somebody like Tiger Woods, however, has more than enough sexual market value to negotiate himself an open relationship should he want one. He didn't, however.

For a while I wondered whether an open relationship would be a scandal as such, and whether this is the reason it is so uncommon among the celebrities. Guess not. I had to turn to Wikipedia to see if there are any celebrity couples in open marriages (more recent than Sartre and de Beauvoir). Yes, there are. Very few. I don't remember any of them being any kind of public scandal.

So, what prevents the guys who want to have sex with a lot of women and have the means to do so from finding wives who'd let them do so without any scandal?