Hi placebicstar,
it is really difficult to know what is going on here. It could be quite different things and possibly a combination of a few.
my partner removed the trigger that kept them going into fits and episodes and has since improved, however they're upset that i never seem angry with them over things they say i should be angry over. they wanted me to stop talking to their trigger, my best friend, which when you're happy and loving both your partner and your best friend (as a friend, no worries) its hard to really say or do anything. i'm not an angry person so i dont know if im being pulled here or what.
1) you are being manipulated. Your partner feels angry and wants you to be angry too. Projection which seems to fall on deaf ears on your side.
This stonewalling of projection is exhausting and invalidating. A better way is to use validation to sling the foreign emotions back. You may need some practice in displaying strong emotions to do that more effectively.
2) you being angry but not feeling it. For whatever reason a disconnect between what you feel deep down and what you acknowledge and is seen by others.
There are many reasons to suppress your own emotions. Not good in the long run. A T may help.
3) you simply not very emotional and/or using weak signals to show emotions.
Practice validation, push your boundaries and explore expressing the stronger end of the spectrum a bit.