Hi sadbutrue, welcome here, I hope we can help.
These are my opinions based on how desperate you seem to be.
When people (and this includes me in my past) are deeply unhappy and sometimes thinking about suicide or other actions of desperation, I turn to radical steps.
I've been there. In 1996 I planed my end, then thankfully I thought of those that love me including my gorgeous two daughters, how they would suffer without me etc. One week later I decided to leave the family home, from the abuse my first wife gave me. A part time dad was better than no dad at all.
Since then I've found that many people in seemingly impossible situations do not consider radical steps to break free from their current situation. A human mind can only take so much hurt. In your case you are struggling to endure your sons drug habit and subsequent behaviour. This must be enormous stress on you. Most of us only read about this and we in society are slowly coming to terms of the difficulties parents like you suffer.
You cannot make your husband "talk to someone". But he has responsibility to the relationship and is refusing to comply with those responsibilities. This is unacceptable.
All that stress ...you don't need other issues. So what steps would I take in your situation? By order something like this.-
1/ Make an appointment with Relationships Australia or similar organisation or individual qualified with counselling. If your husband wont go (ask him really nicely and calmly) then go yourself. After a few visits he'll likely ask you what you have been discussing with the counsellor. Don't tell him. Say "I'm discussing many things...one of which is how to cope with someone that wont seek help". End of conversation. If he loves you enough he'll join you. If he doesn't ...?
2/ Work closely with your GP in terms of your own mental health. We cant cope with everything life throws at us. You are not a superwoman. Be fair to yourself and discuss this with your GP every two week or so.
3/ Be firm one your addicted son. Ice addicts will destroy your lives if you don't. It will be the hardest actions in your life but you cannot allow him to lie to you forever. It is the ICE speaking not your son. Your relationship with your other son needs to be protected. Don't include him in it. The strain will hurt your relationship too much. Your counsellor might suggest he come along to empty his thoughts about your addicted son. Do so.