The punchline on most of the above feedback isn't don't do it. It's don't do it if you don't have cause with some legit basis that you're willing to see all the way through.
On the changing things up & inconsistencies, that's hard on you & hard on the kids. A weekend needs to begin on a consistent night, not redefined by some borderline or narcicist every time it suits her. Otherwise, you & the kids will never be able to plan your parenting time together. Am simply using that as an example -- am sure there are others.
For this matter, you need to either find out what status quo is in your state, or if you're willing to work with her, document your desire to be flexible but insist on consistency. For example, in TX, 1st 3rd & 5th weekends are defined as weekends that start on the 1st 3rd or 5th Friday of the month. So bam -- she can't change that. And if she did, she should only be allowed to tweak it if mutually agreed and if it's firm & stays consistent for everyone. If she then failed to turn over the kids on your Friday, you would have cause to pursue a contempt charge, provided that you follow local laws or firm agreements....and local laws are the preferred scenario.
So your position here needs to be take a step back, stop getting drawn into reacting to her just changing things up & jacking you around, understand what your orders & your jurisdictions interpretation of key terms really means, hold her to it, document it, when she screws with it send a formal letter telling her to stop & to give you comp time, rinse, repeat, then sue.
If you have done the above, you will not be filing a frivolous charge, you will be drawing a boundary then enforcing it per orders & statutes, with a good documentation trail. That's what it is all about.
So with that framework, take the specific things she's done, don't allow yourself to be a door mat, evaluate according to these guidelines, and come back & let us know what kind of specific issues they are. If you can do that, we'll help you structure an enforcement or a doc trail to enable enforcement strategy. If you can't, you have a potentially frivolous enforcement charge where you could get nailed for fees.
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