The thing is it sounds to me like you want to destroy mom's character just because you CAN. Do you think that makes you seem like a mature, rational human being?
If you are a good dad, show that. Show YOU can work with mom, despite what she did/did not do in the co-parenting relationship. Show that you have been providing your kids with a loving, suportive home when they are with you. Show what a great thing it is for the kids to be with you, NOT how awful it is to be with mom. PLAY UP YOUR STRENGTHS! Or, will your "win" only be satisfying if you crucify mom in the process?
And, I hope you and your ex BOTH realize that your kids are the ones who are REALLY getting hurt here. And don't give me any crap about how they don't know. They may not know the specifics but they know on some level mommy and daddy hate each other and are drgging us along for the ride. Wouldn't it be nice if they had at least ONE rational, mature parent. That COULD be you, dude, if you stop thinking in terms of revenge and start thinking about THEM.