I think with all friends you need policies. Like Alex and I agree not to talk about religion, or to take offense when one of us says something, momentarily forgetting this policy. Jake and I have a policy that we are always each other's excuse to get rid of dates we are done with, regardless of how. Ali and I sulk about men together. She hates my exes more than I do and vice versa.
Ali's and my policy has one nasty part. What do you do when they get back with someone? Ali had to do it first when C and I broke up then got back together, Ali hated him. Eventually she chilled out. They get along fine now. But she is my friend, and his by proxy. That is our policy.
Ali and the ex-ex (or as I now refer to him "he who cannot keep it in his pants") are back together. He cried and beg and blamed everything from the whore he was fucking around with to Ali for just being so perfect he felt he did not deserve her (he does not). Ugh, the one thing I do love about our policy is that I can still be snide and trash talk the douche bag.... Nicely. Maybe one day he can redeem himself like C did in Ali's eyes.... Not fucking likely.