It could be stress, being your own boss is not all others think it's cracked up to be, it is hard.
It is hard but stress from work is absolutely not an excuse for ignoring, devaluing or shouting at your partner.
If he is so stressed from work he can't listen to his wife when she wants to talk, he could say "Sorry honey, my head is full of work stuff right now and I can't listen properly to what you're saying. Can you give me a couple of hours to work through what I need to get off my plate and then I can chat."
If the business is struggling he could tell his wife that it's not working as well as he hoped and he's stressed and they could talk together about ways to deal with it.
It's not her job to cajole him into sharing his actual thoughts with her so he will stop treating her like a verbal punching bag. A decent man would have enough self-awareness to know he's behaving poorly because of his own stress and not blame her for his poor treatment of her or refuse to listen when she expresses her concerns and hurt.
OP, he's behaving this way because somewhere inside he thinks it's fine to treat you this way. Nothing you can say will change that. And you'll probably never be able to figure out exactly why he thinks that way or is acting this way. The only thing you need to know is that it's not a reflection on you – healthy and compassionate people who value their partners simply don't behave the way he's behaving.
All can do is decide whether this is the standard of treatment you are prepared to accept from a partner, and if not, leave.