@surprise,
Please get counseling (you can get telehealth these days; check with your insurance company to be sure you're covered). Get some mental/emotional tools to handle all of this. That includes shoring up your self-esteem.
Thoughts of suicide are a big red flag right there, and your taking physical abuse from two separate people also spells a problem with self-esteem. And you're blaming yourself for everything that happened, when your husband certainly is a grown man and is responsible for his own actions.
As for whether you should stay or not,
don't do it for the sake of your children. Please, please don't. All that does is teach your kids that security (which is dubious anyway) and children are more important than personal happiness or even physical well-being.
Only you can decide if continuing is in your best interests, but please don't pin that decision on your offspring.
Finally, the usual caveat applies, IANAD.
Oh, and this is reason #4,357,891 why snooping into someone else's phone is never, ever a good idea.