Anger about situations you can’t control

My husband’s ex-wife claimed their kids on her taxes, even though they live with us and according to their divorce decree, he is entitled to claim them. It made a difference of a few thousand dollars for us. The money isn’t what bothers me. (Well, maybe a little bit.)

Here are my thoughts which I know aren’t helpful:
-The kids are disobedient and disrespectful to me and are a constant source of tension in our home, so I already have some hard feelings where they are concerned.
-I have all the responsibilities of being a parent to them, but none of the rights that come with parenting.
-My husband won’t stand up to her because he’d rather keep things peaceful.
-I make the majority of the money in our house, yet feel like I have no say over this tax situation which does affect our finances.

Here’s my model:
C- Ex-wife claimed kids on her taxes
T- This is so unfair
F- Resentment toward husband and kids
A- Withdraw from husband, get irritated with kids
R- Division in our family

Can you make some suggestions for a new model?