Legal Question in Family Law in Washington

If you mean liable for violating a provision of the decree of dissolution, then I'd say that you need to bring a motion for contempt for violation of the decree, or a motion to enforce the decree, depending on what exactly has been or not been done. You can then ask for attorney's fees as part of either of those motions, and if you prevail, you are likely to be awarded some or all of your attorney's fees and costs.