I'm going to play devils advocate and look at this differently.
If you really did a wrong thing and deliberately killed them when it was wrong to do so - then you should be consulting an attorney and not posting about this online.
My guess is that the police and the DA investigated and found that you did nothing wrong. That what you did was legal - and it is legal for a very good reason! US law allows us to do what you did because it recognizes the right to defend ourselves.
If the DA did investigate and you are facing any legal action related to the incident, stop posting online and get yourself a damn good lawyer, now. Pronto.
You may actually want to at least consult with an attorney either way because if the families of the perpetrators who broke into your home come across these posts where you write about all of this, they could use these posts in court against you. You are "anonymous" here, but yet not that anonymous. What you post here could be linked to you. I'm not trying to dissuade you from posting, but just advising you to be cautious - and even more, this is all the more reason to get yourself into therapy.
They generally can not use what you say in therapy against you in criminal or civil legal action. (Not unless you authorize access or other very rare exceptions that usually involve future imminent threat, like suicidal intent.) Either way, therapy is a much more confidential and legally protected place than here.
If you are not facing the threat of legal action and you are still convinced, so convinced of your self blame about their deaths... all the more reason to seek counseling.
Your action to defend yourself do not change the need for you to get counseling. Even police officers who shoot in proven self defense are put on leave and evaluated, and many suffer PTSD from such incidents. Even if your self blame is legitimate, this is still very real trauma to see people die in front of you.
Even if these criminals had not died, and you had somehow survived another way, you would still likely need counseling.
I feel like you are trying to heal by trying to change your husband, trying to find peace and solace from him and with him... You won't ever get there if that is how you try to go about this. Not even if he was a really stand up guy. (Which he has proven to not be a stand up guy, again and again.)
We can sit here all day and tell you that you don't deserve to blame yourself like you do. Chances are, you will still keep blaming yourself or trying to change your husband, until you are ready to face the truth. Your life was in danger. Your daughter's life was in danger. You naturally have many symptoms now from this horrible event. You need help to heal. It's not your fault you need help. Anyone in your shoes would.
The simple act of seeing someone die, no matter the cause, or the fact that your lives were in danger to begin with, is enough to cause most if not all of the symptoms you are experiencing now (inappropriate guilt being only one of the many symptoms you are facing.)
There is a path to get better.
That path involves you finally focusing on you, your pain now, and all of the aspects of this mess about your husband and these horrible people who put you in danger and put your daughter in danger.
That path to recovery includes getting your butt into therapy. No excuses. No trying to self blame yourself out of it. No more making your recovery contingent on your husbands actions.
If you can't yet go to therapy for your own sake, do it for the sake of your daughter. She deserves a momma who had support and help to get through this time and recover.
You focus so much on what you feel you did that hurt others but you don't focus much on how much they should not have been in your house putting your life in danger and that of your child.
You are so quick to focus on your blame and so quick to try to get your jerk of a husband back, you sound somewhat like the abused wife who keeps trying to go back to her abuser because maybe this time it will be different. You are steeped in denial and inappropriate self blame so much, so ready to ignore really awful things that others have done and to try to make jerks like your husband happy, that I wonder if you have been through trauma even before this.
You can't bring them back to life or make this better by blaming yourself. You can't bring your husband back from his decision to divorce you by taking all the responsibility for things that were not your fault.
We can not "rationalize this life." Trauma inherently involves irrational shit happening. It probably wouldn't change much about your symptoms even if we could.
But we can support you and your effort to recover and let go of all this self blame.
It will be very hard, but you are made of strong stuff and I believe you can do this. I believe you and your daughter can have a very bright future ahead of you.
P.S.Based on what you have shared here, it seems like you did the right thing, and even if you didn't, I don't think you deserve all the blame you put on yourself. I think it's really survivors guilt, or the common shame and self blame victims feel after trauma, and not accutately deserved guilt or self blame. You were scared, in a dangerous situation, and I would have likely done the same thing myself. You are a mom, and you have some very good and healthy momma bear instincts that kept you and your daughter alive! You have much to be proud of. Yes, proud. I'm glad you survived and I am glad you are reaching out for help. I would be more worried about your recovery of you were cold and didn't second guess what you did. But it doesn't mean your self blame is accurate. I hope you can find relief and a safe place to work through all of this soon.