Do you ever wonder how or why your dad hasn't separated from your mother?

My mom and dad have been married for almost 25 years and i honestly don't know how my dad hasn't gotten divorced. She drives all of us crazy, honestly i think there was something wrong with her when she was born that went undiagnosed. She is a nightmare 8/10 times. She drives the whole family even my dad crazy. All she does is eat/sleep/ gossip/ bring her friends over at unexpected times/ talk **** about my dad (harworking man). Honestly i've cried so much that sometimes i cuss her parents (internally) for raising such a bad mannered daughter. She brings us all down. She tells every little detail about our life to everyone. She has ruined many family friendship cause she gossiped and said the things she shouuldnt. TODAY, my dad woke up vomitting, I was giving him medication and other remedies and my mom was shouting and keep shouting that a drawer was missing. I told her many times to stop now cause my dad is lying down and sick. Finally my dad snapped, throw his iphone 7, shattered which is not working anymore and went to the hospital. Honestly this is just an example. I feel like I'm going to explode any day. She doesn't care about any issues. My dad pays all the bills. Everything, literally for everything and she complains how my dad doesn't give her money (which she steals daily). She is so embarassing that i don't let any of my friends to come to my house or meet her cause you don't know the things the more embarassing things she would do
Is anyone in a similar situation?

Added (1). Honestly, her family doesn't take any blame, I tell them to like tell her something but they say 'she's your mother, respect her,' blah blah. I feel like they've thrown their left over to us and we have to deal with it. My mother wanted to go visit her family and they said no don't come now, its not a good time. Like i serioulsy am dying inside slowly. I'm tired of seeing my dad being treated like this or me and my sibiling.

I went back in time and had sex with my great-grandmother.

My parents separated when I was in grade 11 (they're now both deceased). My mother moved away, so I stayed with my father and took care of him until he passed.