I get the same way. I know how hard you are on yourself and how difficult it is for your DH and kids. I'm glad you've posted because it really doesn't need to be this way. CBT with a good professional can really help you manage this. You probably won't be able to extinguish this behavior but you can learn to manage it so it doesn't flare like it does - damaging you and damaging your relationships. It will also be helpful to learn the CBT techniques and teach some of them to your kids. They're useful skills for many situations, not just those that people like us blow up and turn into huge, crushing, overwhelming events.
FWIW - I don't think you're really thinking of killing yourself but it it's not healthy, even in those brief moments, to have suicidal ideation. The problem is that if you don't interrupt these cycles, they could actually lead to suicide or self-injurious behavior (research backs me up on this). I've seen someone describe it as a feedback loop that strengthens and reinforces itself. It just get worse and more difficult to interrupt over time. Learning CBT won't be a years long endeavor but it will take years of using the techniques to get you past this habit. Until you can find a therapist, you can use Dr. Google to get you started. Hugs.