Your emotions have burned out. Over the years, you've probably been through a nightmare. Things that people should not have to experience. Added that from, what I am guessing, is a fragile emotional disposition, and you have emptiness. Incapable of truly feeling anything real. Am I right?
What KHfanatic and several other people on the first page have pointed out, seems like the most reasonable and logical suggestion: a certain emotional numbness by now, that resulted from going through horrible things again and again.
It's sort of like when you're having a really bad day. Over the course of the day, every possible thing has gone wrong and gotten on your nerves. And then, at the end of the day, when that one last thing fucks up, you just don't care anymore.
Hey, maybe you think you didn't feel true, overwhelming saddness when your partner died because, deep down, you were steeling yourself for the possibility that s/he may not make it. Sort of like a foreshadow, so when the true moment came, it wouldn't be as intense as it could be.
This might be a possibility though, too. I have my own experiences in that department, too.
You might have been already so "emotionally detached" towards that person (for example because of a lack of contact with that person over a long time period or whatever), that the reaction you got wasn't the one you would have expected. It is like the grief that you felt was purely based on your memories and the fact that he is who he is, and not on the emotions and feelings you have towards that person. And because of that, not seeming real to you.
But yeah, all we can give you here, is just mere speculation. :/
Either way, I don't think this is something one can blame on oneself.
