OP,
Teens at that age can be very trying.
I can imagine how upset you are.
But it seems while things have been simmering for months and have finally spilled over.
I certainly don't think your long marriage is over, nor do I think you should kick your husband out......I do however think it is a big wake up call that the dynamic in your family needs addressing.
Your husband was wrong without a doubt.
He is the adult and should know better.
But he is human, and he has made a mistake.
Your son sounds very gobby, argumentative and annoying...I had two like that, both my son's....I used to say they would argue with their fingers🙄....exhausting.
I think you need to sit and really talk to your husband about what brought him to this place and what can be done to prevent it happening again. He needs to offer up what he is going to do to ensure this does NOT happen again.
I think you need to sit down together with your children and acknowledge that what happened was wrong and that it will not happen again.
I think you need to talk to your son about how he's feeling and how he is behaving.
Some family counselling could be very helpful.
Happy families are NOT created by one person, everyone plays a part.
One member constantly behaving badly will sour things for everyone.
No one member of a family can be allowed to sour the atmosphere for everyone.
This needed to be reiterated a couple of times during the teenage years here!
Your son needs to be told to buck up, as does your husband.
You are rightly terribly upset at a this incident in your home.
You OP need to very firmly lay down the law about what you expect from your family.
Violence is NEVER the answer.
Tell them clearly YOU will not tolerate this petty baiting of each other, any longer.
They BOTH need to grow up.
They both need to apologise to their sisters and you for their behaviour and upset.
OP, they both need to see YOU assume control and tell them clearly to buck up.
Obviously as the adult here, your husband needs to be majorly onboard and own his part in this, before you can move forward.
Wishing you the best.