I went through a divorce, and the loss, while undoubtedly not as intense as death, was quite severe. I'd recommend Katharine Kubler Ross book "On death and dying" to understand the five steps in grieving. That gives understanding, though grieving isn't something you can rush through. I've counseled a number of folk who have lost a partner to death, and everyone grieves at their own rate. However, the cycle of denial, anger, bargaining, and other steps are pretty standard for everyone.