Why do we except pain from spouse but not others

my husband was in jail for murder for 14 years and i knew about it before i married him. he doesnt like me to ask him any questions and he is always doing drugs and talking to women in person or online also he has nude pictures on line and always hanging out late...i am tired of his abusive mouth and he has hit me in the past a few times. i have told his family and they turn the other way. he recently went to the doctor and was dx with bypolar.. he doesnt work and complains about any and everything that deals with the house or my 2 boys..i want a divorce and he has said several times that he hates me and dont want to be with me and dont like my ways because i go into his phone and i will delete it...he has packed his bags several time but wll not leave...i am tried and i want him to leave. we have been married 1 yr and been together for 6 yrs...he wasnt always this bad and now i dont know how to handle or to take his weird behavior...his family just takes up for him and i dont have any friends and my family are not close..i move from md to pa because he wanted a fresh start but i cant mae friends or go out becuase he takes and pick me up plus i work 7 days a week..my children work and he always ask them for money . we are behind on bills because of his drug problem... i have research the point of no return and i am in need of help....or ideas....thanks