If you really want her back simply give her what she wants, and you may well succeed.
Accept her as she is now, accept she wants to be free to do her own thing without having to explain. Be the stay at home dad, or help with majority of childcare, whichever is most doable.
Most of all stop asking her to explain herself. The woman you see now has changed beyond all recognition of the woman you married.
She won't turn back,at least not anytime soon. And neither she should if this is more to her liking.
Stick around, do as she asks and be happy and non judgmental about it. And eventually you will have her back to some degree.
But it's not going to be the way it was.
If you Love her, then just let her get on with it and be their when she needs you.
She will work it out in her own time...all you can do is wait. There is no figuring out why. And tbh it doesn't matter, you want her back then accept who she is now, stop trying to shoehorn her into explaining why, and work your life to fit around hers.
You want her back but only if....?
There is no 'only If' she is who she is and that's fair enough. Just accept her and her new friends if necessary.
She still loves you and your certain she does, just accepting who she is and letting go what she has done should be enough to give you a starting point.
All the best.