Depressed, anxious and lost.

I have suffered with anxiety and depression for 20+ years and my parnter has bi polar disorder. We have been together twice. The first time we were together we split up when he had a manic episode as he terrorised me, I had called the police several times as he attacked me at work and I was scared to go anywhere he was constantly ringing me and messaging me, which I just ignored because any time I spoke to him, if he didn't hear that I wanted to marry him and move away he would scream obscenities at me, also sending horrible messages and trying to demean me to my friends and family. In the end after nearly 3 months of this torture he was arrested and jailed. Which I didn't know at the time, I hoped he had given up. He suddenly messaged me out of the blue to explain he had been ill, been arrested and jailed and transferred from prison to a secure mental health hospital. He apologised profusely and asked my forgiveness. I wanted nothing to do with him and told him how much he had scared me and that no matter how ill he was he knew he was wrong for terrorising someone he was supposed to love. We kept talking (to cut the story short here) we got back together, we have a 2 year old together now.

I want to end the relationship, but I am terrified he will go off the rails and I have my son to think of now. My depression is bad and my anxiety is the worst it's ever been, i've been suffering panic attacks, my health is suffering, I feel sick constantly. I can't make myself see the dr as I panic everytime I am due to go to the surgery for help with my health. I comfort eat when I don't feel sick and have piled on weight, we haven't been intimate in months. He seems fine sleeping the clock round or playing computer games and seems to think everything is fine, but when he asks I say i'm fine because i'm scared of his reaction. He hardly spends any time with out son as he is either asleep or playing games, but he thinks simply being present is enough.