Okay, hope your therapist is working with you on these issues, but what you're telling us, what you are saying here is a bunch of hooey that you're telling yourself. That you're just a hysterical kind of guy, that you're going to get all emotional when you go to court, that it'd be better to just not show at all, since you're just going to mess up so terribly. It seems you've given yourself all sorts of excuses, and now you're telling yourself that everyone is judging you and you're going to screw it up. Okay, stop doing this.
Go to court projecting sanity and confidence, taking all the suggestions offered above. Concentrate on making it look like YOU are the sane and stable person, more so than she is, in this court appearance. If she's a bit manipulating, controlling, got the tendencies from her family, well, thank God you've escaped! Now use this court appearance to make a clean break. Forget negating all the proofs and evidences and texts she may have kept that are from you. Yes, they may make you sound foolish, but you're over that now. You may have been foolish, but you're moving on, right? Let the court see this!
It would be better that you get an attorney if you can possibly afford one, but in any case, be able to tell the judge (your Honor) that you are getting therapy and working on your past mistakes. What the judge hates is someone who doesn't show (they'll listen to every word she says about how nutso you were and are still) OR someone who shows with a hopeless shrug and a hopeless future ("Yes, I did it, but I'm just that kind of a guy, and she broke my heart and the next time I get a chance I'll do it again, women shouldn't break my heart this way!") Not to mention "Boo hoo, I'm just an abused child with lots of issues and I deserve a break because I just can't control it."
What they want to see is "Yes Sir/Ma'am, I may have made some bad decisions, I became emotional, perhaps a bit over dramatic, but I have been moving on with my life, I am seeking help and getting on the right track and there will not be any more problems from me in the future." You can do this. Don't let your family or anyone else tell you you cannot! Good luck to you.