If you are frightened of what you might do

Then treat that as urgent rather than as a thing to manage on your own, and do not wait for it to happen before you tell somebody.

Today, if you can. A doctor, a helpline, a family member who can take the children for an afternoon, or an emergency service if it is that. In many countries there are parent helplines specifically for this, staffed by people who hear it every day and are not shocked by it.

Asking for a child to be looked after for a few hours is not giving up your child. It is what an adult does when they can see the edge of something. The parents who end up in the worst situations are almost always the ones who could not say it out loud to anyone.