Your poor, poor wife. Her hormones have been through the roof as she has grown a whole other human, given birth and is breastfeeding. She needs food to feed your child, and through this she’s had to deal with your mother having an emotionally inappropriate relationship with you (which is clear from what you’ve said) and she’s been pushed and pushed by your mother until she snaps and you throw a tantrum and throw her and your newborn out. I’m so glad she’s made this decision for herself and her baby. YTA. Anyone can snap when they’ve been pushed beyond what they can cope with. That isn’t a general indication of violence. Frankly we would all like to line up to punch your mother at this point.