I don't think there is neccessarily a right answer to this question. It depends on the circumstances and the volatility of the situation. Personally, I've never been much of a fan of dating within one's own group of friends, as it is often more awkward, more likely to cause complications, and brings along extra "social" baggage in addition to the usual, personal kind. To me, It's like dating your hot second-cousin; There's nothing especially illegal or immoral about it, and the sex may be good, but others are likely to frown on it, and your left with the nagging feeling that maybe you should be "diversifying your portfolio," so to speak.
I think cooling off period is always in order to step back from the situation and decide what you should do. Was the breakup messy? Are there hard feelings all around? Does your friend or your ex seem to be over the situation or are they hanging on to the hope that the relationship may be salvaged? It never ceases to amaze me how some people stuck in these kind of situations can't manage to wait a few weeks for people to sort through their emotions, and instead jump right into a touchy enviroment and end up having everything blow up in their face.
I once had a friend start dating one of my ex-girlfreinds about a month after we had broken up. To his credit, he approached me and told about how he had run into her and been talking to her the previous weekend. They had made tenative plans to go out that saturday, but he had the guts to come to me and say "I'd like to go out with her, but if this is going to get you all pissed off and make things difficult between us, then I'll just take a pass"
When he started to tell me, I felt a twinge of jealousy and anger start to build up in my gut, but the more I thought about it, the more I remember that she wasn't right for me, that I was foolish to hang on to any remaining hopes of things working out. I felt an awfully deep respect that my friend would have the both the courage and empathy to tell me the truth and ask me how I felt. I had never handled it that well when I was in his position. While I was prepared to give him my blessing, I decided to ask him one quesion. "And if I say **** off, don't do it?" He said "Well, there is lots of ***** to go around and we can both go nail a couple of drunken skanks this weekend" LOL Just thinking back about it makes me laughh. What a bro!
