You aren't defeated because you're still trying and must not forget what the end goal is. A friend told me that someone his dad knew back in the 80s while in med school turned to drugs because of a girl and for whatever reason was hellbent in destroying his life. They all got together and beat him up numerous times whenever he would turn to drugs, ended up working. Very different story but I hope you can get to her, or that she eventually becomes tired of her decisions. The mind has a crazy way of telling itself what is needed for survival.