You need to turn the tables on her by showing her you can stick to your guns and not go crawling back every time she snaps her fingers. She's obviously thinking "I'll kill his ego so he won't go looking for anything else." Well baby or not, I think you've got to maintain your distance from her while still being responsible for the kid in the best way possible. If you keep this up long enough, I'm pretty sure she'll relent in the end, especially since she's alone and will likely feel overwhelmed at the prospect of having to raise a kid by herself. I hope that's what happens, because it would mean a much-needed power-shift in your situation with her. If she can't change her ways and continues to belittle you, just be there for your child and leave her to her own devices. That's really all you can do.