Husband (29M) and I(30F) want to keep his sister(36F) a secret from our future children
Me (30F) and my spouse(29M) has been together for five years and married for almost two years. I knew he had an unhealthy family dynamic but I never understood the extent of it until I married into that family. His father was extremely negligent towards his wife and children. His older sister (36F) is the one this post is about. We are considering hiding her from our future children completely. English is not my first language so please bear with me.
Background: His sister ran off and married someone when she was 16. None of her parents approved of this marriage. However she still kept extorting money from her parents in promises to leave this guy. There has even been instances when his mother, the primary breadearner of the family returned home with her paycheck for the month, and she stole the entirety of it. The way my husband puts it is that he knew education was his only way out. He was crying and studying every day and that's how he got out of this small town and got into a good university, where we met. His sister never graduated High School. His mum went to college and tried her best to give both of her children a good education, but was not able to succeed in any way with his sister, aka her eldest.
When I got married, she was 35, and had just left the previous guy after having three children with him. I naively thought she had suffered a lot in her life and if we show her kindness, she might try to get her life together. I encouraged my husband to have more of a relationship with her. His mother had passed away by this point. A few months into our marriage, my husband was offered a good opportunity in Europe and moved there. I would follow him in a year. Then his father had a heart attack. I had to organise his care and treatments, while his sister tried to take over his business and properties, essentially trying to steal from her brother. I somehow became the primary caregiver to her children, while she went off honeymooning with her new guy. She became really abusive to me. I was still trying to do my best for their family, giving into her demands and essentially pampering her. I did not quite understand that I need to cut myself off this situation for my mental health. I was being taken advantage of the same way my mother-in-law was. This woman is good at taking full advantage of people's empathy. My husband was not okay with me taking care of her problems but I did it anyway.
It clicked together for me when I found her living in my house, eating my food, berating my husband over the phone, when I was taking care of her children. I was okay with me being disrespected because I excused it as her trauma but my husband being disrespected was something that crossed my boundary. She was soon asked to move out.
After my father-in-law passed away, my husband came back from Europe and oversaw the property distribution. She started spreading rumors that my husband did not give her any part of their inheritance from her mother's death. He was happy to give her 60% of their father's property to 'clear his name' so he never has to contact her again.
Much to our surprise, she started spreading the same rumor after her father's estate distribution was completed. By this point we both had zero contact with her. I moved to Europe with him and we're together now, drama free for the last six months.
Recently someone let us know that she is spreading violent misogynistic propaganda against me on her Facebook account. She is accusing me of prostitution (I'm an engineer, lol) and having an abortion (which is none of her business, and she has had multiple abortions) She is implying that I'm such a vile woman that my husband has cut off all communications with his sister because of my manipulation.
Of course for us the best course of action for us is to remain in no contact with her and her children. She tried using her children (she had a new one with her new guy, essentially baby-trapping him) to get into contact with us, but we did not budge.
Now that we are planning to have children of our own, we are seriously considering telling them that their father is an only child. I don't want her to even know my children's names. My worry is that I someday disclose to my children when they become an adult that they have an aunt, and out of curiosity they try to reach her, only pain would ensue. She is very good at playing the victim, that's how she survived thus far. I discussed this with a friend of mine (30F) who advised that it's better to not have secrets. This does not seem like a good idea to me. What if our children feel when they know of this that they can't trust us anymore? I do want to raise healthy and confident children. Having someone like her in someone's life can bring no good.
Which is why I am asking reddit, how would you feel if when you are 18 or older, your parents revealed to you that you have a secret aunt and four cousins? Would you feel distrustful of your parents? Would you think your mother is making any of this up to make the other party look bad? What if they think we have been on a fairly prioritizing one side of the family over the other?
What is the best way to deal with this?
TL;DR: Abusive sister-in-law, we don't want our future children to know of her existence. Friend thinks honesty is the best policy. What's the best course of action?