I find that by expressing it, I can let it go. I had a long period of bitterness/resentment, etc. - and was able to pretty well move through it . . . the feelings cycle - and today this came up . . .
Part of the frustration in dealing with alcoholics/addicts, is that you cannot have a normal "fight" with them to clear the air - you can't say any of this stuff TO them (because you want to be supportive and not blame them or cause further traumas or damage to them) - it's the unexpressed stuff that then becomes toxic.
My resentment is much less than it has been and I also feel a lot of love for him - the two feelings coexist - the anger and resentment tends to go underground and when it is suppressed, causes depression.
I can always tell when I get depressed that there is some rage/resentment or sadness I need to process - and once I do, the depression lifts.