`titrebA first love is (almost) never forgotten`/titrebThe treatment of borderline cases shows an « undesirable » loyalty to the primary object, such that the problem might be: how to move from a memory to an autobiography, to deflect the mass of real by preventing it from being imposed as a destiny, to introduce a migration ? How to work on the hatred and feeling of possession that characterizes these patients ? The author suggests that it is also through hatred of the new object that a movement allows various modulations and transformations of the original configuration by carrying out a process of disidentification. The theoretical and technical problems relating to these complex dynamics are raised with reference to two clinical cases.