Okay here's the thing......
IF he CAN (can being the operative word in this sentence) BEHAVE or (as you say be contrite) control himself when police are there? Then he CAN behave. This is not any pearl of wisdom from your Auntie Star. This is a fact from a very well -rounded, expensive, helpful, authored therapist we saw for years. Your son is NOT a child. He's 16 years old. So the potential IS there for him to KNOW when to control himself and HOW to control himself, it's just that he DOES NOT KNOW how to do it ALL.THE.TIME. This is where behavior modification therapy would be EXTREMELY helpful.
Refusing to do things? Part of being a kid, a teen, an angry child. It's the ONLY way he has right now to control a situation that HE otherwise? Has NO control over. HE IS ******. He's angry about a lot of things in his life and you, and your X have just gone on your merry way and left a wake of **** for him to sift out figuring that once the arguing and trouble between YOU and X calmed down the problems for your son would calm down too. IT DIDN'T. For him? It left him with MORE questions and MORE anger and a lot of it? He may not even be consciously aware of. It's just THERE. HE is 16, probably functioning with the emotions of about a 12 year old and added to that are the fact that he's falling behind in school, hates school, his parents are split up, he's a teenager and that alone in todays times are tough. The economy is tanking.....and he's angry. REALLY REALLY angry like you can NOT imagine and has NO PLACE to just GET ANGRY - and how to deal WITH what he's feeling. Sometimes you have to just get to thearpy or have a big brother person step in and be a mentor. At 16 - they really do NOT want to talk to and confide in US - but a total stranger MAY get them or get their attention or even their loyalties. Weird - but true.
He needs help-----and he's a bright kid. He's not a loss, he's just really frustrated...and YOU? You can't go to him and say ARE YOU MAD? Because it will make him shut you out even more. IF HE will not go to therapy (and he won't) THEN YOU and your X - need to put the BS aside for a while - and GET INTO THERAPY for HIS sake. Find out how to at least come together and Get on the same page and be a UNITED FRONT FOR YOUR KID - otherwise? You probably WILL loose him. Sad as it is to say that - he's living with Dad, angry at the world....and you two need to find middle ground and help fast. Help for your son. Eventually maybe there can be some resources - because at 16? The stakes and the consequences are NOW - ADULT consequences. Life in prison is now a reality - 30 years for burglary is NOW a reality. And these kids don't think. They react.
I sound harsh - but I've already lived it. I'm living it now. And we went to therapy.....and it DID help - not right then for our son, but now - and he's 20.
And if your X doesn't want to do this? THEN YOU GO. YOU GO and get some answers and ask questions to a professional that you are asking US - other parents. See if what I say is true. Because it may not be just such a truth as your circumstances may be a little different....all I can advise you on is how OUR life was - and go from my experiences...but between the lines what you wrote? This is what I see.
Glad you found us - It takes a lot of courage to step out of your comfort zone and call the police - and especially on your son. While it does make a paper trail? It's not the best answer all the time - And an out of home placement doesn't necessarily come unless you have a LOT OF PAPER TRAILS......and a LOT OF hospital visits. True - you both may need a respite - but I think your son needs a respite from his anger and needs to learn some Anger management techniques FIRST - before he can function ANYWHERE. THAT would help him in my humble opinion more than anything.
Hugs -