Its easy to say to cut off, but its never possible. You will have to just wait for her to die soon. The only thing you can do is accept that she cannot change, its her heartbreaks, her abuse, her misfortunes she is throwing on you. Vent out whenever you feel too overwhelmed, my mother is very very similar. I deal with her taunts, mood swings, everything else like her husband, even then I am not enough. These parents think the way of life they know is the only one their child should follow. For your case, you can never change how your mom is, she might understand for a second but u cant change how she has lived for so many years. According to mine, she is elder so she is right. only work on yourself. Get away from conversations impacting you or your kid and husband. Approach this with only you and your fam in mind