Lmg, I would second naej on this. It takes a while to get to the point of being grateful for the good marriage, but I am now. It is like all grief, initially you mourn the loss to esclusion of all else, but eventually you come to appreciate what you have and accept the loss. But you don't get there in five minutes, or even five months!!
I was distraught by grief for the longest time, but we have to go through that period of mourning. If we suppress it we cannot fully move onwards.
