Emmy,
You sound like a wonderful woman that a rational, non-addict, non-abusive man would be lucky, and appreciative to have. It sure sounds like you really do the best for your children.
The one thing you can't give them is their father sober - that's a choice he had to make for himself. But you can take them out of an environment where their mother is verbally, and potentially physically abuses in front if them. You did nothing to cause his behavior. I've known wonderful, lovely women dating addicts who chose drugs and alcohol over a stable life. I have known upstanding, loving, intelligent, hardworking men whose wivrs chose addiction at the cost of their marriages and children. It's not your fault. It's not something which reflects upon you at all