Stuck in relation ship with step dad

Its hard to sum up so fast but i will try..feel free to ask more...mom was abusive / neglectful .. Poor and bullied .. Her bf was only one there for me .. Mom had kids with him.. 3 i pretty much raised since i was 7 ..when 12 he got kids away from Her.. When we came back it was kind of a normal life me and him where friends we smoked weed and hung out .. He got to a point he would no longer let me date..so i went online for fun.. He caught me and called me names for it .. We fought for days then he told his feelings too me.. I thought i had to stay for my sisters anyways till i was 30 and i figured he would never let me date ..i was dumb 18 and wanted sex i knew he was clean..it was dumb but i said ok i went with him.. I didn't know it meant forever .. Just when i was going to maybe go he had a stroke.. Its been 6 years with him now.. I don't have friends and my family is in dark about us..i feel trapped but also like i made my choice and that a little slut like me should just shut up and deal with my choices ... I want to leave but he depends on Me and loves me ..i tried to get out once and he said the blood will be on my hands..i wanted to seek console but it seams it all costs money .. Please any one ? Help me?