Dating ex sister in law

I am a former model with an Executive MBA from Wharton/Columbia, undergraduate and graduate.I want to stop seeing my sister-in-law but is this right?While we will be polite to our brother's new wife, I don't imagine that we will ever have the type of relationship that we have with his former wife, our sister-in-law, who has been a part of our lives since we were young adults.Is our brother right to demand that we end our relationship with his first wife?To make matters worse, the ex-girlfriend is a psychologist/lawyer and was privy to many goings, which she has altered.My new sister-in-law has made me feel uncomfortable with personal attacks that are deftly done. For the first couple of years I was in a sad, isolated, and withdrawn state. My wife’s younger sister moved to my city to begin her medical residency more than two years ago.I understand the topic is awkward and her parents and I have had a strained relationship.

Dear Taboo, I’m assuming you’re not a member of the Inuit or Chiricahua people.

My new husband of two years was involved with a woman before me for five years.

Even though he told her to stay away from his sister and told his sister to stay away from her, they persisted in their relationship.

So now my daughter is going to have a baby brother or sister that is also her cousin?

I dont want my daughter around that situation and since my ex has pretty much been a dead beat dad the whole time, I think I have the control as to whether or not she is in that enviornment?