Help leaving husband

I have been with my husband for 10 years… he has not worked in 2 years and I have supported me, My 3 children (2 from a previous marriage and one with my husband), him and his 1 child, (all together 6 of us… and I am going further and further into debt). He has always been a jerk… but I have always thought “he will change when he gets older”… He has done everything to me from Cheat, hit me, go to jail over drugs, etc. I have finally reached the end of my rope… BUT… how do you leave someone that doesn’t work, depends on me to support him and his child (which I love), Stays at home all the time, Drives me to and from work (with my own car, he has NO car), and I am Deathly afraid that will get violent with me.?? Everytime I tell him about my feelings he tells me I am nagging and tells me to shut up… when I tell him I want to leave him, he either trys to make it a joke, gets mad then takes it out on the kids (yelling and treating everyone like crap)… So I just drop it and go day to day just trying not to cry… Our marriage is crap… We do not give each other compliments, hugs, kisses, etc. We fight everyday… and It is a good day if I go the whole day not being called: Lazy, fat a@@, or a Bit%h…(in front of the kids). I mean what am I teaching my kids? ALL GIRLS… that it is okay for someone to treat you like that?.. I would leave him in a heart beat… I just don’t know how to do it, without the FIGHTING… Physically and mentally. I wish there was a legal way for me to start the process of legal seperation or Div. without him knowing, get my stuff and move out (which the house I pay for and the title is in my parents name) until I can get him to move!!! WHICH is a whole other story… **he has a felony (2006) and no one will hire him and he has to stay in this area, because of probation… … MY PROBLEM IS HORRIBLE!!