Trust Issues with my Mother

We are due for a baby boy in August. I am having some second thoughts about letting my mom around our baby.

My parents split when my dad left my mom for her compulsive cheating and trying to hide drug use. Since 8 yrs old my mom has been in and out of my life, usually calling every several months just to say she's alive.

When my oldest sister graduated from high school she fell into a bad social circle and dad told her she needed to move out or stop her reckless ways. We were always worried sick about her, sometimes driving around until 4 am because her car was missing and her cell phone turned off. We sometimes wouldnt hear from her for 2 weeks until she came back home to get more clean clothes. Anyway, she decided she didnt want to follow my dad's rules and said her solution was to go live with our mom in Texas (and her stupid ex-druggy husband). My dad bought her the plane ticket because they just couldnt reason anymore.

It was a hard day for all of us. She flew out halloween day and at the airport we all cried and my dad pleaded that he could take the loss of the airfare if she just wanted to come home and try to turn her life around. My sister still wanted to move with my mom, so we let her leave.

Less than 60 days after moving, my sister became pregnant. My mother is on permenant dissabilty, so was her husband. They were lazy, never worked, but sat on their computers playing WOW 18 hrs a day. My sister went to work all through her pregnancy waiting tables and went to cosmetology school at night. My sister paid most of the bills and funded their cigarettes, even paid my moms car payment. When my nephew was born, my mom and her stupid husband watched him while my sister worked. At about 1-2 yrs old, my moms husband got custody of his 9 yr son somehow. This kid had an IQ of literally 28 and was socially, metally, physically underdeveloped. It turned out that my mom and her husband isolated the 9 yr old and my nephew in their room all day which was actually a small laundry room with a bunkbed. It turned out that the 9 yr old had been molesting my nephew. My nephew is now 5 and out of that house since a few months after CPS was called by my sister and our family supported her financially to get back to CA.

I just keep thinking how my mom hasnt changed. Not even in being a grandparent. She is entirely selfish and she has said that what happened to my nephew wasnt at all her fault and that hes too young to be affected by it. It makes me sick.

Now that I live in DC, my mom messages me all the time and even sent me a giftcard through the baby registry. She divorced her husband and lives in New Jersey with her soon to be new husband. Shes always saying shes available when I deliver and can help us transition with the newborn. My husband is aware of all of my mother's past, and I know he would never insist on kicking her out of my life, but i know he cant be comfortable with the thought of my mom and what she allowed to happen to my poor nephew.

I dont know what to do?? I definitely dont want her staying with us at all to help with childcare. But am I selfish to not even feel like i want her to meet our baby??