I completely understand that anger that is hard to look at and deal with. Most of the last few years with AXH, I was pretty numb emotionally; when I started feeling again, any emotion was scary. But, emotions come and eventually they'll go. If there's bitterness attached, looking at what's behind those emotions will help that bitterness move on, too.
I stopped keeping a journal while I was with AXH because he'd find them, read and then use everything in them against me whenever he felt the need or desire to put me in my place or hurt me. I started again after I'd been away from him and was starting to process everything. My art journal from that time was full of a lot of heavy charcoal drawings that, honestly, look like screaming.
I was also told anger isn't a bad emotion (my therapist and my sister both). It's what we do with it that carries repercussions. Anger lets us know when our needs aren't being met or if something's wrong. It's also often like a default emotion that covers up a lot of other emotions that are just too messy to deal with. (In my case, my therapist noted, it was probably easier for me to be angry than to admit I was scared of the man I loved.)