I'm going to be blunt: Her vagina and her mental state have been through a whole lot of trauma in the past few years. Birth, sick pregnancy, miscarriage, sick pregnancy, birth again. Ay yay yay! I wouldn't want a penis anywhere near me if I were her. Especially if it means she might get pregnant all over again. Do you have any idea what goes on in a woman's body and mind throughout that entire process? It is a monumental transformation, it is painful, it messes with your hormones and compromises your mental health. She needs to be exempt from sex for a while, with no penalty.
All you can do is be gentle with her and kind and loving. Recognize all that she's been through and tell her that she is amazing for it. GENTLY remind her that you want to find your way back to a loving relationship again. You want her in your bed, and you want to feel welcome to touch her and hold her. And then let it breathe a bit, with no expectations of sex. Promise her you'll wear protection so she won't have to fear another pregnancy.
She's been through sheer hell and needs respect and some time to heal both physically and mentally. Please, please be patient. You will have your love again.
It's been 14 months since the birth of my son, and I still have a few raw nerves (both mental and physical) from the birth and the first few months of the shock of being a new mother.
I hope this perspective is somewhat helpful to you.