There is a stigma surrounding endings. The world round it would seem that endings are almost unanimously considered bad or the saddest part of an event, book, or what have you. This is not the only angle that endings can be seen from. Endings are complicated things that can leave those involved wholly dissatisfied or completely content with the proceedings. They can be so much more than just an end.
Endings can be things of beauty. That could be why there are so many sayings surrounding them. One saying that comes to mind is when God closes a door, he opens a window. When one thing comes to a close there is always something else waiting in the wings. A quote from Lao Tzu reads "New beginnings are often disguised as painful endings." An end can be a chance to find, or start, something better. In fact, certain endings can also be helpful.
The end of a bad relationship, be it platonic or romantic, can be a good example of this concept. Getting away from this thing that only drags you down and makes you miserable can only be a good thing. It probably will not end tied up in a neat little bow. Tears, betrayal, and a general sense of sadness are just a few of the side effects that come from this kind of ending. These feelings do pass, and then it is simply a matter of finding the right distance to see how that particular ending was a very good thing. It can be akin to cleaning a wound and finally letting it heal as opposed to allowing an infection to fester.
There are many ways that endings can be both bane and boon to those experiencing them. A relationships demise is only one example among many. And as for those sayings listed above, there are many more than the two given. An ending can undoubtedly be a miserable affair, but sometimes they don't have to be.