Oh Lucy, I read your story and could have cried for you.
Everything you say rings true, and reminds me of my past situation. My husband is 18 months clean, but was using on and off (mostly on) for the 12 years we have been together.
You really need to get out of this, I appreciate he is your baby’s father, but he will drive you insane.
After 10 years of torment (the last 5 being the worst) I tried to take my own life. To be fair, i was not actually serious, it was a cry for help, and a way to escape from the drama. He was doing lines of coke while I was led on the floor after taking too many codine and paracetemol. I remember him being nice as pie to the ambulance people, but to me he was so horrible, why did I do something stupid like this? What was I trying to prove? I had to get a £60 taxi home the next day from hospital because he wouldnt collect me and I couldnt tell anyone what had happened, because his drug use was not widely known.
He too was convinced I was cheating, I was not, yet he was.
There is nothing you can say or do to stop him doing coke, coke is the most important thing in his life. If you try to stop him, or give him reason not to do it, you are trying to control him. An addict never sees it as you helping, they see it as you stopping them doing what they want.
If you can leave do, go to parents, please. Your happiness and your childs happiness is the most important thing, and you will end up going mad if you stay and he doesnt want to stop.
Sending love x