My sympathies for what you're going through BrotherDan. I'm not sure I like the idea of telling her it's all your fault and you'll try to be a JW again. Simply, because its not true and I don't think a marrriage can survive long term if its built on a foundation of dishonesty and mistrust.
I think what you could tell her, which is true, is that you are on the same path. You both still believe in God. You both still believe in the Bible. You both love your children and want to do what's best for them. Those are all paths you share and those are the big ones. Disagreeing about Bible interpretations of what Jesus and Jehovah and the apostles MIGHT have meant, are the small things and not worth rifting a family over.
You could then point out some scriptures for her that agree with you. There is one somewhere about not fighting over words and interpretations. There is one about Jehovah hates a divorcing. There is one about not leaving an unbelieving mate who is willing to dwell with you. Read those scriptures to her calmly and with love. Tell her you are willing to stop talking about your different interpretations to her because it is causing fighting and emotional upset. (This is not the same as admitting your wrong or agreeing to be a JW). Tell her that you do not want to divorce her. Tell her that you are willing to dwell with her even though she doesn't believe as you do. You are willing to follow those three scriptures. They are main ones for counseling Christians on differences in marriage and belief. Is she willing? Ask her? Ask her to explain why she is not willing to follow the scriptures on these important family matters? Ask her is she truly believes in her heart that it would be more upsetting for your son to see mommy and daddy disagree, resolve it or call a truce, and continue to dwell together, than it would be for him to have a broken family?
If she tries to pull the "spiritual endangerment" excuse, tell her that you are willing to stop talking to her about religion and endangering her spiritual viewpoint. In return you only ask that she respect your right to not go to the KH or listen to her viewpoints. In short, call a truce.
If she wants to save your marriage, she will agree to your terms. If she doesn't, some part of her probably wants out or wanted out anyway. Many JW's have this delusion that they can get rid of the unbeliever, wait for them to commit adultery and live happily ever after with a good theocratic brother. If she seems to want to go that route, you can remind her that the odds are not in her favor. The life of a single mom with small kids is a hard row to hoe for a regular woman, never mind a JW. Don't make it too easy for her.
If she insists on separating, don't help her by moving out, or helping her more than what is your court ordered child and spousal support. Insist on joint custody and use the JW crap against her in court to get it. It is against the law where I live to alienate one parent due to religion. Document every case of her doing this starting now, before you ever separate. Dates, times, word for word in a diary what was said and done.
You may lose your wife. In the end, that's her choice. It won't be because you were unreasonable and didn't compromise. It will be because deep down, that's what she wanted. You do not have to lose your kids too.
Hope this is helpful. Please let us know how it unfolds.
Cog