Oh, OP. Sorry about your health 
Listen, in a healthy marriage, people don't wonder whether they need to walk away. They love and feel loved - that question isn't on the radar.
Now sometimes people feel they should walk away because of issues or insecurities of their own, and yet they are loved and they need to work on their anxiety or have counselling or whatever to feel more secure.
But often, when someone feels they might need to walk away from a marriage, it's because their instincts are telling them something. And they need to listen.
It's hard to know from your words whether your husband has fallen out of love with you, or is being an abusive dick, or is just really scared. But for what it's worth, when my husband was very ill, the last thing I thought about was how he was looking or his weight - apart from where those things were indicators of how his health was on any particular day. And I was aware of being even more overtly loving than I had been before, because I was so worried about him, and scared for him.
One thing you said worried me a lot.
When he's had a few beers, he just gets so cross about the slightest thing. It's like he's super fed up and all this hate comes out.
This sounds awful. In what way does the hate come out?