This is an interesting question, moodycow. I recall watching a program on physics on our local public TV station. At one point in the program it was stated there is no such thing as cold. There's only an absence of heat. I think despair may be similar. It is not an emotion in-&-of itself. It is, rather, the absence of emotions, both positive & negative.
I live with allot of despair. Much of it is related to things in my past for which there is no remedy. There is nothing to be done. So I simply work on living with it &, as my signature statement below says, accepting it with compassion & lovingkindness. It can be tough to sit with thoughts of despair. But the alternatives: trying to ignore them or to stuff them back down, only make matters worse in my experience.