Not my first time, but my first incestual experience

I'm a 32F. I was sexually active since I was 18, so this isn't my first time having sex, but this was my first time having sex with a relative. <br><br>I have a brother who is 36. We've never been close in the past, but he got married and moved in with me for a little bit because him and his wife were saving to move to a bigger house. So me, my brother, my SIL, and her daughter (my niece) lived with me for about 3 months. <br><br>My SIL was my age, so we got to talking and I found out that my BIL was cheating on my sister. She was (and still is) devastated, and hasn't moved on at all. But my BIL didn't want a divorce. He just wanted to stay with my SIL and get to do whatever he wanted outside of their marriage. He got my SIL pregnant twice but neither of them lived, sadly. The stress of my BIL's cheating was probably why. <br><br>So, despite being married, my SIL and my brother hooked up one day. It was after a good drinking session between the two of them. He was so nervous and guilty after but she said 'don't feel bad. I'm not happy or in love with my husband' so they continued to see each other. <br><br>My niece started acting strange last month. She's only 11, but she's said some weird things to me like 'men will do what they want' and 'you can't make a man love you'. So I sat her down and asked her what was going on. She told me that she walked in on my brother and SIL one night. They were in the middle of having sex and my niece said she saw my SIL's behind in the air and the look on my brother's face. It was a man who was screwing. <br><br>My SIL and my brother were mortified. I suggested she go to therapy to work through her feelings but she said 'I don't need therapy. I'm fine.' She was distant from my brother and SIL for a while, but they're all good now. <br><br>My BIL called me last night and asked why his wife hadn't left him. I told him that she was too afraid to leave him, and he told me he was going to divorce her. <br><br>My SIL is actually pregnant with my brother's child. They were going to get an abortion but decided to keep it. It's a boy. They're thinking of naming him Atticus.