i would say allot of it sounds like bipolar. it sounds like he is also maybe experiencing the hyper sexuality that can come with bipolar, maybe not. if so the lies could stem from guilt or the avoidance of guilt and or anxiety.
on one hand he probably needs you to get through starting meds and therapy and on the other you can,t help if your sick. just as he has a certain level of responsibility for his own treatment you must take care of yourself first.