Ah the hell with it beat his ass! }:) I am so sick of pussy footing around people I cant take it anymore. IF he pulls that crap on your property and the kids aren't around let him have it! If you chose the mature route then record it in some way or fashion and turn it over to the police. Let him have one last rant to record and if it happens again hang up.

In my experience bullies are loud and abusive to who they perceive as weak. Once someone stands up to them and means it, many times they will back down because bullies are cowards at heart.

I would intervene simply to warn him at first that you've had enough of his threats and verbal abuse towards your wife. You may not technically have a legal say in the child support but you do have a right to protect your home, the kids, and your wife from any abuse. Warn him that if he can't act like an adult, you will get involved and it won't be pretty. Be vague about what you will actually do so he can't cry to cops you threatened to do this or that. Just general terms. Continue the court/lawyer proceedings. Do everything in writing from now on via email or text but be careful what YOU or your wife says. Save everything he sends.

If there is a physical confrontation? Just stand between him and your wife and make eye contact. HE has to throw first punch or shove. Then it's self-defense and you can crack the prick in the face.

I think it's time you stood up for your wife even if it's just verbally. This kind of a bully also isnt sparing his kids, trust me.

My ex was bullying me the same way for a few years now.Never physical violence, but horrible emails , texts and phone calls .Mostly about child support and also about changing all responsibilities with the kids in his favour, which almost always meant I had to change any plans last minutes to be there for my kids , even on days he priorily agreed to take them .Vice versa he "demanded" the kids when it suited him in my times, but at the same time 'forgot" them at school etc.He made my life hell and I had panic attacks when his name came up on my phone, I felt helpless, scared to death and worried all the time.I asked him to go to mediation but he refused and even lied about several letters he reveived from the mediation officers.Lately he is with a lovely lady who grounded him a bit, but as a matter of fact I really dislike , almost hate him for what he has put me through the last few years.It is a shame - we got separated because we had drifted apart , there was no cheating or anything similar bad- I always assumed that the separation could be clean and we could have stayed civil and friendly, but I was wrong.
When ex did the same - dropping child support gradually and finally half it for no reason I had finally enough and after a few warnings I organised the CSA to be collected from him.He threw one more really bad fit and tried to abuse me verbally , but afterwards got the message.I never wanted spouse support which I was entitled to, I was happy with less CS beforehands than what he was supposed to pay,I kept on paying certain bills for him, eg rates, but he got worse and worse.I actually think he showed me more respect when I did go to CS and asked them for help.
My recommendation is to work with your wife and help her through the emotional struggle and try to set up collection for the CS.DON'T do that bully a favour and engage with him on his level.Hitting, screaming whatever does not solve the problem.You need to stay calm and work on your and your wifes sanity in all this, focus on yourself- don't do that bully the favour by being upset and angry.This is all that freak wants to achieve.Learn about your rights.

>At what point do I stop being "the bigger man" here and tell him that he's not going to be doing that anymore or there will be a consequence?<

My advice is going to differ from some of the people here. Based on my experience (my wife's ex was a bit of a bully as well), my advice is as follows; the less YOU deal with the ex, the better you BOTH will be in the long run (especially with a court date coming up). Any AND ALL communication between your wife and her ex should be kept between your wife and her ex and that communication should be done in writing only. If he calls, she should ask him "Are you calling to report an emergency concerning our children?" If the answer is no, she should tell him to send her an email about what it is he wants and then hang up the phone.

lozo - document everything. Copy every email, text, etc.. Accept no more phone calls from him. Get call block on your phone service. Block his phone number and tell him he must text from now on or write a letter. Or go a step further and say all communication (except an emergency with children) will be via attorney. When he has the kids tell him to text (it is harder to yell and scream when there are limited characters, unlike on emails.) Block his email address and accept only texts or letters in regular mail. Make sure you make the teachers of the child still in high school aware of the situation. You don't know what he is capable of pulling. Have them ALWAYS check with your wife if he makes any demands. I'm not saying he doesn't have a right to know about his children's lives but the more people that know about his behavior, the better.

Child custody payments are ordered by the courts. If he doesn't pay (without substantiating a reduction in salary) then he is in contempt. Hold him to it.

Keep detailed records of all payments, time he spends with the children, his lack of cooperation with children's schedules.

And by all means get the police involved if he makes any threats. Record and document EVERYTHING.

He is a bully and bullies are cowards and many will back down when confronted. However, it sounds like he also has a mental illness. Any chance the courts could force him to seek treatment? Pursue all avenues. You do not have to live like this.

Good luck.