na,
I really sympathize with your situation. I have been there. My husband addict died 12 yrs. ago, and I still struggle. You are so right about the boundaries part of codependency. No one says that doing for others or spreading joy is something to be avoided, it's just that when that becomes harmful in any way, and takes away YOUR capacity for joy and full functioning----that's when help is needed. I sense a bit of defensiveness, but I know...I reacted that way too. To me, if the joy of others is something I attach so much of ME to, then if their joy somehow doesn't turn out...then mine is affected to my own harm.
I know it's hard to understand...and sometimes I don't even know what I feel. The long and short of it is that we CAN ONLY control our own behavior...and not others'...it's as simple as that.
Be well,
msm