Does anyone knows?

So it has been a week since my divorce,  am not crying or angry about it.  Maybe it was because I cried a lot the last 3 years over a broken marriage.  Is it normal for me not to feel sad?  I mean am kind of relieve.  What is wrong with me?  Aren't I supposed to be grieving?  Am not.  I feel stronger, but I keep hearing from friends that one should work in themselves after getting a divorce or otherwise will make the same mistakes.  So does anyone knows how long I am supposed to grieve?  Even though I don't feel anymore grieve or sadness at all? 
My relationship was at times full of domestic and emotional abuse, infedelity and other problems.  Now am just fine, does it means that I am going to breakdown later?