Oh Op, l am so very sorry you feel this way, please focus on the fact you are blessed with 3 beautiful children, you are their world.
This horrible man is making you feel this way, just kick him out....what could possibly be harder than living with that awful behavior?
Nothing, in fact it will all get much better, happier Dcs , no stress for you and without his financial drain, more money for you and Dcs.
You can make friends once your life is on a better footing, in the mean time post on here there are loads of womens who have been through similar who will support you on here..
Also unload to the Samaritans, you are struggling mentally due to the stress of this vile man, get rid of him and your MH will improve....imagine the relief of putting your Dcs to bed and having a long bath and book with no interruptions, no drunk abusive man crashing in....
Please leave him, you have a job and home it is possible. Handhold from here..