Married, Separated, Divorced???

Question, is it ever ok to date a married man? I know most women probably said "hell to the naw" just now. But there are various states of married. There is the plain old married man, the separated man, and the man going through a divorce. Are any of these phases a green zone for dating? The first category is probably an easy no. But what about the second two? A number of things brought on this blog. I have personal experiences of married (though claiming to be separated) men trying to get time on my calendar. Now I don't judge anyone, but my personal feeling on the issue is that married is married. Even in a separation the two could still work things out. Heck even soon after the divorce they could work things out and I would hate to be the one factor that stops the couple from their potential reconciliation. Besides, if a person is still married on paper it kind of makes you feel like the dirty little mistress if you entertain a romance with them. And we won’t even get into all the potential emotional baggage they are probably dragging along with them. It’s just not my speed. But many women would argue that separated is as good as single.

I was speaking with an associate the other day; she's currently in a very serious relationship with a married, but separated man. Allegedly, he is reluctant to officially leave his wife b/c of the children in the situation. So he has his own apartment, while the wife and children live in his former home. He has a key to the house and is able to come and go there as he pleases. However, he assures this associate that he is only interested in the kids, not at all in their mother. She says she is quite happy, trusts him completely, and believes they will one day get married...OK, stranger things have happened right?

I also have a former coworker that believes any man is fair game. Her logic is "if he's coming after you then clearly something is wrong with the relationship, so go for it". I'm sure this is the less popular view, but in the age of high profile mistresses gaining fame for their indiscretions its clear many women are perfectly content being the other woman. Are these women wrong, selfish, stupid, misguided? Or are they just opportunistic?

So, I sincerely pose the question... Is it ever ok to date, pursue, or entertain a married man?