Needing relationship advice

I need advice! I have been with my partner for 11 years, and those 11 years have been a rollercoaster. Our history is a long story full of all sorts but I am going to try to keep it to the present. After 11 years of mostly pain, lies, deception and manipulation with a touch of happiness, I finally said enough is enough, something I have said many many times before but always get sucked straight back in and feel like its happening again. Ive been staying at my mums for the last 9 months on and off but just recently received a eviction notice which I am happy about because now its out of my hands and no longer will be sucked back into having to go there. I have to add we have a daughter together as well as 3 kids his side and 2 on my side but our daughter is a 7 year age gap between the 2nd youngest and 11 year age gap between the eldest. Anyway, the whole relationship we have been on drugs, I have tried many times to get clean but it is almost impossible to do so living with a addicts and he will tell you he wants to get clean but has never made any real attempt to try. 9 months ago a bunch of blokes came to my house and bashed him while my daughter was inside over owed drug money, they threatened to come back and do more and not just to him. So myself, my son and my daughter ( other daughter lives with her dad) moved into my mums. over the next 9 months I kept trying to kick the habits and provide a lifestyle my kids deserve but it has been nothing but a challenge. He is the best manipulator, I gave him the nick name MnM, master manipulator and some how keeps pulling me back into the hell hole he lives in. But i kept trying, I am now clean, just got a job, starting to feel better and starting to gain the respect a trust from my loved ones again. Still to this day he mentally abuses me, manipulating me to stay there, once he has me there its like im trapped and its not easy to get away. He does stuff and says things that makes me scared to leave sometimes, so a few weeks ago i said I am done and was sticking to it, until he finds out his dad only has months to live. So now not only himself but also his family are putting me through the guilt trip, telling me basically I should put my feelings and pain aside and be there for him because of his dad, telling me im heartless amongst other things. He loosing it because he knows im serious this time but now hes acting crazy and traps me and scares the crap out of me. I still have a lot of my stuff at the house that i need to move before I have to hand the keys back but im too scared to go there. My question is am i being heartless and selfish? Should I put everything aside and be there for him? I dont have anyone to talk to or ask advice from! I do want to be there for him but not as his partner! Ive been hoping, wishing and waiting for things to change for over 10 years now because I know he could be a good person if he wasnt on the drugs but nothing has changed, the whole time I have been with him he hasnt had a job, been in and out of prison, always promising he wants to and will change, but it all ends up being empty promises or straight out lies. Im scared and want to break free and live a simple, normal life with my kids instead of being a disappointment. I want my kids to be happy and proud to have me for their mum.