I'm sorry you are having such a shitty time 2anddone.
I left my twunt ex last summer and am so much happier being a single mum. I know this has been a shock for you and it's different but I'm sure you will cope.
What I would say is this, and it kind of comes from recent experience but mostly is regurgitated advice from fabulous ladies on here who know their stuff.
Don't engage with him, say no and mean it. He cannot walk in and out when he likes, do not take what he says as gospel about money.
Find a good local solicitor and speak to them(you should get a free half hour) about housing/money/contact with the dc.
I've seen my solicitor three times, been stronger at each letting and the resulting letters have been enough for my ex to stop bullying me and thinking he can do what he likes.
Have a good look through the relationships board, there are some ladies who have been through so much and their strength and conviction has Ben an inspiration to me. I only wish I had toughened up and approached solicitor earlier.
Good luck, keep your chin up, feel free to pm me if you want to offload, as ive said im not an expert but i can listen and call your dh any name you want me toother posters did this for me and it was such a help.