Your mum sounds as nearly as nice as my mum.
It could very well be a mental illness. My mother (57) has been diagnosed with everything under the sun and the diagnosises keep changing (Currently, she has been diagnosed with General Anxiety
Disorder, Bipolar, Borderline Personality Disorder
, and Obssesive Compulsive Disorder) She always has had a temper, but menopause
made it MUCH MUCH worse. The family is starting to think now she may be not metally ill - but just has gotten away with bad behavior for so long and no one has really called her on it until now and so now she is furious and out of control. As children, my sister and I could not do anything as we would have been punished immediately for "talking back" or being "disrespectful." When she couldn't handle us, she would loose control and go beserk.
My mother is a huge manipulator and blames everyone for everything except herself in which she claim has "never done anything wrong." She even says that her abuse towards us was my dad's fault because "if she only had a loving husband she would have been able to deal with children better."
My dad, like yours, has not the best husband and has been quite a jerk in their relationship. But honestly, I believe my dad could have been perfect in the relationship and she would have still found fault with him.
Was it menopause that did this - or did menopause exacerbate it? Is it mental illness or just really bad behavior?
Trust me, I completely sympathize with your situation. It is extemely hard to deal with someone like that.
Personally, I don't believe menopause "does this" to a person. When does the person become accountable for their actions? If menopause causes such massive mood swings, then she needs medical help
What I would also most importantly recommend is getting help for yourself. Not that there is anything wrong with you - but coming from personal experiece, this situtation puts a TON of strain on a person. Therapy will help you learn to deal with your mother in a more constructive way and help you cope with the frustration you may be feeling and help you not to carry on the behavior unconsciously.
I am sorry I cannot offer more help. I wish you all the best and hope that things improve for you and your family.