Friendship formula

Does friensdship require a certain number of calls/texts/emails/stupid forwards per month to mantain it's defination? I never thought it did... I have BFF's that I can go months with out talking to and then pick up the phone and chat as though not a moment has passed. I have friends that I email, some that I call, some that I text and some are simply sustained by playing "Words with Friends" and talking smack to each other. Of course those friendships weren't forced, nor did they happen over night, they took years of give and take. Oh there were lots of other people that came acroos my path, but not everyone is destined to be a lifer, you know? I have "phased out" friendships just as I am sure someone has phased me out too. The difficult thing I am facing now, is someone who after a short period of time, and of an odd circumstance (the new girlfriend of our favorite couple who are now divorcing) wants not only to be my BFF, but without any effort on her part and assuming I will choose between the ex-wife and her. (that may not be entirely true, but I do feel pulled) She sent me a CRAZY long email the other day of 95% rambling and 5% wanting to know exactally where she stood in my "friends" line... How do you answer a question like that? Let me rephrase, how do you answer a question like that without hurting their feeling AND without lying? I told her that it wasn't awkard that our favorite couple has a new girlfriend, what is awkard is that it's as though he brought in a new quarterback and we are all just suppoed to pretend we didn't notice and nothing changed. The reality is, it's a new team, with a whole new dynamic... and even if the quarterbacks are equally skilled that doesn't mean that the team will be equally successful. Only I was super sick, with a fever and was a bit more abrupt... she never responded.