Anger is formed also due to attachments, we cling to things as ours when it can easily be said they are not ours as well, such as our partner, or pet, property and body these can all be called someone else’s as someone else made them or grew them, or are another being.
I think anger comes with a confrontation to our identity, of who and what we are, and it is this ignorance which stops us enjoying life to the fullest, by causing us to believe that which is not, instead of that which is, and by causing ourselves to see, and do that is for ourselves not others, but of course this is a common trend for everyone not just one, or two people.
When we realise we are angry we lose some of, or all of our anger, I think this is due to anger not being part of us in the conventional sense, but jumping in on us when we don't realize. Anger like all emotions isn't who we are but a mask that we, or the emotion puts on ourselves for a short period of time (something like Venom in Spider-Man), no more, no less, just a part of our repertoire of who we pretend to be, and it is this thinking which gives us a sense of how things should be, which opposes how things are, which causes anger, as anger is only the result of a delusion not being compatible with reality.
At the end of the day I may be right, I may be wrong, but I share this hoping I am one or the other.