However, is it really "temporary insanity" or one of the many terms that is thrown out there to give a reason where we have none - just like fog or mlc. Mere terms to justify. The thing is, they don't love or care for us - if they did, then they damn sure wouldn't sleep with someone else. What most here tend forget is that there are different levels of love - sure they can still love us in some form/fashion, because after all we had a significant relationship with them. And people fall out of love/caring all the time...so why should they be expected to stay? Ever ended a relationship yourself? Same deal.
Now, with that said, sometimes they just don't care enough to want to continue. It happens. And stop with throwing terms/bones/etc at them, because that's exactly what it is.
The real problem here on this board is the LBS. We tend to think and try to explain their stuff through our own eyes and experience, when, in reality, it doesn't fit. We need to work on ourselves and stop trying to do everything in our power to get them to stay. If they decide to come back, then that is a different kettle of fish. Call a spade a spade and let it be done.
There are moments in this life when you are so confident in the rightness of your actions, that not even for a second do you consider the option that you might be wrong.