Welcome
! Congrats on your upcoming birth, I hope that all goes smoothly and your baby is healthy as can be
I second the suggestion for a vet visit to rule out any physical cause for the accidents. It sounds to me like you've been doing everything right
She readily accepted your husband, so in theory she would also accept the baby. That's why I'm leaning toward a bladder/kidney issue. Gosh, I hope you can figure it all out, hopefully someone here will have better advice for you.
Good luck and keep us posted. Oh, and we LOVE pictures here, so feel free to post lots of pics of your girl