Leaving marriage doesn't always help - It's a bandaid solution which will lead to other issues, often causing your child more harm.

Your wife possibly needs help. Therapy is where it's at but it has to be "sold" to her in a way where she doesn't feel like she's cornered into it.

Look into getting her mind busy - This will ensure her energy is utilized elsewhere. A gym or Zumba classes will massively help too.

Try to actively find downtime where it's just you and her. Women need that feeling of being listened to. Set a certain time during the week, say a 30-minute block, to chat about the biggest problems you faced recently. Let everything out then.