You are not turning into him, he is just making you very angry & no doubt very stressed.
When I saw a DV woman, her advice to me was to log everything, including things the children say & exactually what happens, and date it.
Have a safety plan. Have copies of important paperwork, be sure to have an extra set of keys, keep your mobile charged & with you at all times & work out where you could go quickly if needed. Maybe you could stay with your mum or a friend in an emergency.
Also keep spare clothes at either a good friends house, or maybe your parents house, for both yourself & your children.
You really do need to make an appt with the CAB, & then a solicitor to find out your rights with regards to your house etc.
It is very very hard to make the decision to break free, but your life sounds very unhappy atm, & you are clearly walking on eggshells constantly. I don't think that leaving will be as tough as the life you are living right now tbh, & one day you & your children could be living a far happier, more relaxed lifestyle.
Good luck.x