If a wise person goes to court with a fool,
the fool rages and scoffs, and there is no peace.-Proverbs 29:9, NIV
Cheaters hate your boundaries. They despise accountability. They want what they want, and they want it NOW!
I say this to remind you that their anger does NOT mean you are in the wrong. In fact, it may be an indication of progress on your part in maintaining a healthy boundary.
You are changing the rules of the “game” no longer tolerating their abuse.
When you file for divorce, they may become angry because they no longer control everything. They have to face others who may rule against them. It is not a high school break up. They have to deal with real adult issues–like the legal system–as a marriage ending is an adult ending.
Be safe.
I hope you plan for this not unlikely reaction to you setting needed boundaries. Cheaters–like tired toddlers–hate being told, “No.”