B.O.U.N.D.A.R.I.E.S!!!

Limit phone calls. Email and texts are better (paper trail). And do a bit of research, is it legal to record phone calls where y'all are? (It differs from state/country)

Be BUSINESS LIKE every time you have to communicate with her, brief convos, very very brief and facts only. Don't get carried away with big discussions, you only end up saying things you'll regret. Sorry, by *you and *you'll, I guess I mean your DH, because HE should be the only person dealing with his crazy ex. But he has to keep that in mind, she IS his crazy ex, she KNOWS how to push his buttons to get the reaction she wants. (It took my SO 2-3 years to learn to avoid falling into BM's crazy traps)

Stick to the CO, NO FLEXIBILITY what'so ever! (with these BM's, you give'em an inch, they take a mile!)

From years of dealing with an intrusive ... of a BM, what I've learnt, is that it's best not to fight her, be smart! be fair! be pleasant! So that when she does drag you off to court, all her "evidence" is in your favor.

As someone else said, recognize your power (yours separately and yours and DH's together) and stop letting her wreak havoc.

If she's recording phone calls, no more phone calls. She's got no reason to call you so block her number and don't pick up numbers you don't recognize. DH and her do need to communicate, so he needs to set a boundary with her. In writing: "BM, unless there is an emergency or a last minute schedule change (which should not happen often) I would like to stick to email communication only." Ignore her rants. She doesn't get to unilaterally define what communication looks like.

Then, when she calls DH (because she surely won't let him tell her what to do), always let it go to voicemail. He can listen to it soon after if he's worried. Then, assess whether it is something about direct parenting that he needs to respond to (emergencies, schooling, extracurriculars, physical or emotional health, schedule change requests) and respond to her in an email. Do not respond with a phone call after you've told her you want email communication only. If her message is not one of these things, ignore it. If it is partially about the kids, only respond to the part about parenting.

Same with texts. Respond with email. Don't allow her that instant access to DH because she will abuse it. She needs to be slowly cut off. She is deliberately causing conflict because conflict is something that she likes. It's attention, and positive and negative attention both reward her, unlike most people.

Pick up a book called "BIFF: Quick Responses to High Conflict People" by Bill Eddy, as well as "Say Goodbye to Crazy" by Tara Palmatier. Read, incorporate.

BM isn't a normal rational person who will come to her senses. She is an unhappy person and is projecting it all onto the two of you, and feeling in control of you will make her feel in control of herself. The only solution with her is to put up rock solid boundaries and cut off her sources of power.