Hello again, stay strong and this time apart will do you both good. You could always ring up a drug helpline like FRANK to have chat with them and they maybe able to give you some advice or signpost you relevant people.
People can easily get addicted to drugs and yes it ruins lives and families but with the right drive they can come off. Its never an easy road but with the right support it can happen.
Getting to the root issue is vital, I have seen people deal with the outer layers of addiction and they come off, make some changes but their demons are still there and come back in different ways. He needs to address his whole being, emotionally, physically and spiritually.
Addiction support, counselling and positive changes to his life/routine/interests will help him on the right track.
But thing for sure is you can not help him, he has to do it, he has to take all the steps, contact the support and make those changes. It has to come from him, he has to feel in control of his life and you can support. It may have to be from a distance at first.
You may look back in time and see even though this was an awful time for you but by standing your ground and making him see what he is set to lose and how it upsets and effects his family will in time turn it around for you all. You all deserve to be happy and you have started that change.
If it does not work out and he does not fight to make life better and you go your separate ways you have shown your children, that they come first, you will always protect them and you will be a great model showing them how to stand up and protect themselves.
Sending hugs xx