Do not blame yourself for his anger. It is not up to you to change how you carry yourself to make him less angry. It is up to him to learn to control himself.
Does he suffer from depression at all? I ask because for about 20 years my dad has long been of a similar spirit, often, perhaps daily, flipping out verbally at my mom on the weirdest little things, though without any physical destruction and without any violent actions. Now there are no heroes in my parents situation because my mom gives it right back just as much. They kind of feed off each other in a massively dysfunctional co-dependent loop of arguments and belittling. It's quite damaging if there are kids around to the kids I'm sure because I can even see some affect on myself and my younger adult siblings (they still live there).
I ask about depression because one time recently my dad mentioned to me that he has felt depression ever since his mom passed, which was about 20 years ago...and around that time was when the arguments really escalated and have been what I would consider emotionally abusive ever since. I've since wondered if depression is the cause for his outbursts, and instead of being sad and mopey or apathetic, the depression manifests as anger? He is now dealing with significant heart issues so that is his current health focus but he agreed that should his health get better that he should then focus on his depression. i wouldn't be surprised if there is something mentally my mom could work on as well, she's has some quirky behaviors too but I can't quite pin it.
I also noticed you mentioned a particularly bumpy time after your husband had an operation, and I know many post op complications can br increased depression. So maybe he really needs help with that to calm down? I think if your husband is willing to get some counseling it could help. Maybe I'm just projecting here based on my family situation, as in hindsight I wish that years ago I was more adamant to my parents that they get help. I don't think it could hurt... although the discussion to get him to go might be very difficult.
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