Op l felt so sad reading your post, you and your dcs deserve better, please up your standards and get rid of him..
A partner should Lift you up, make you feel comforted and supported.
He drags you down....deliberately, it will never really change.
I am sure you can do this if you make lots of plans for what to do when you are feeling anxious as pp said.
think back to what you used to enjoy pre Dcs.....can you make a plan of say 10 easy things to do when dcs are not with you:?
Even as simple as, ring x friend one morning to lift your spirits, have a long bath, read a favourite book, call y friend in the evening to avoid feeling lonely...there must be hundreds of things you used to enjoy or wanted to try or learn when you didn't have a family to take care of, well now is the time,......
Make a huge ME poster of all the things you will do and once you have told him it is over, put it on your bedroom wall and start.....!