Have a read and think about how many unwritten, unspoken contracts influence your relationships with people or expectations in your life?
If you recognise yourself as displaying codependent behaviour in some shape or form then I wonder where on the Karpman's Drama Triangle you are on. Lynne Forrest's Overview of the Drama Triangle explains and describes the dynamics of the concept very clearly. There's also a good succinct article at ways of breaking the drama triangle.