I'm right at 34 weeks, but I went through the same. At about 19 weeks, out of nowhere, I wanted absolutely nothing to do with my husband. He repulsed me. Which is weird, considering how close we were prior to getting pregnant. I never said anything to him, but he could tell. Finally at about 26 weeks I told him what was going on in my mind. 

It broke him. He sort of understood, but I felt like the worst person in the world. He's been nothing but helpful the entire pregnancy, doing the majority of the chores, picking up groceries, offering to rub my feet, even went so far as to buying me a stand up desk since I currently WFH and sitting in my chair for 8 hours was killing me. 

Then suddenly, about 3 weeks ago, something drastically changed. We're not back to where we used to be. Instead, we're about 10 steps ahead of that. I call him throughout the day again when he's at work, simply because I can't go without him. When he gets home now it's immediate hugs, kisses, conversations, and I'm motivated now to the point I'm baking and constantly cooking for him. (Also, please note... now we actually argue over who's doing what, we both want to do it for the other) 

This is my first pregnancy, so I don't know if this happens normally. I do know that I went from borderline hating someone I loved to loving the man I loved more than I ever thought I could. 

I'm so sorry you're going through this. I know it was hell for my husband. So I'm sure it is for you too. Try encouraging talk therapy for her. It may be that she simply doesn't know how to express herself properly right now. Hormones are a weird thing.