You don't want to change!
An important part of masochistic stuckness is a primal scene.
The subject altruist tried to help the phallic mother (substitute) and although he or she went to great distances the phallic mother wouldn't change. When they come into therapy, be careful that you don't put in too much effort to be practical with them. They've entered projective identification with the phallic mother and now want others to try with them but won't take help.
In a similar variation of the proto phase (instead of the deutero) the altruist will frustrate friends and intimates. They will be too busy with other things and the intimate will feel like the altruist is being selfish, like they want to be chosen but the altruist chooses another, and like they are being avoided.
In altruism there are such subtle little hurts that are passed on to others and its interesting to think about how many therapists coach others when so many of these interactions are repetitions from earlier ego injuries.
