AITA for calling my SIL a selfish jerk after she asked me to lie to my husband so she doesn't have to miss our wedding?

TL;DR My (F26) fiancé (M31) and I are getting married next month and we are so excited! We are having a small wedding at a cabin in the middle of nowhere. My SIL (F29) is really close to her fiancé (M32) and they are kind of douches. They live in another state and they want to fish on the day of our wedding. She asked me if it was okay if she brought him to the rehearsal dinner so she doesn't have to miss our wedding. I said sure. She asked if it was okay if they leave for their fish after the reception starts because they didn't tell any of their friends they were coming and they can't make it to the wedding after the cave closes. I said it was fine. She then asked if it would be okay if I lied to my husband and tell him she's at the wedding so he wouldn't get upset that she left us for her empty promise of fishing. I said no. She cussed and said I was an asshole for ruining her promise of fishing and asked if it would be okay if I just pretended I was the one who got sick and she went with me to the hospital. Finally. She got mad that I didn't let her miss our wedding to lie to my husband and I called her a selfish jerk and she called me and screaming names at me.<br><br>***************<br><br><br><br>My (F26) fiancé (M31) and I are getting married next month and we are so excited! We are having a small wedding at a cabin in the middle of nowhere. My SIL (F29) is really close to her fiancé (M32) and they are kind of douches. They live in another state and they want to fish on the day of our wedding. She asked me if it was okay if she brought him to the rehearsal dinner so she doesn't have to miss our wedding. She didn't actually want to bring all of her friends, just him. He doesn't like making small talk with people he doesn't know. Also, he doesn't like children and our wedding has a lot of kids. Our family loves kids so it matters that he doesn't like them, but we didn't care because we knew it was hard for her relationship to survive the miles. I said sure. I figured if I made her happy, she wouldn't try anything else. She asked if it was okay if they leave for their fish after the reception starts because they didn't tell any of their friends they were coming and they can't make it to the wedding after the cave closes. My wedding is at 6 p.m. and this is a cabin in the middle of nowhere. The cave closes at 7 p.m. The reception ends at 10, though. So, if they left at 6 p.m. they could find their way there before it closed. I said it was fine. She asked if it would be okay if I lied to my husband and tell him she's at the wedding so he wouldn't get upset that she left us for her empty promise of fishing. I said no. She asked if it would be okay if I just pretended I got sick and she went with me to the hospital. Finally. She got mad that I wasn't going to help her and her empty promise of fishing. She asked if I was an asshole for ruining her promise of fishing and then I called her a selfish jerk and she hung up on me. Then she called me and yelled at me some more. I am unsure if I am the asshole.<br><br>_______________<br><br><br><br>I think there has been confusion. My SIL is leaving when the reception starts. The cave closes at 7 p.m. So, she will leave before then. Also, she wants me to lie and tell my husband she is at the wedding. I do not have to attend the wedding to know if she is there or not.<br><br>_______________<br><br><br><br>It's been brought to my attention that a small number of people are assuming my husband and I are abusive because my SIL said we are. My SIL is also being used to frighten my husband's younger sister. I wanted to put this issue to rest. My husband and I are not abusers. We do not abuse SIL. We do not abuse his sister. We treat everyone with kindness. We are good people who do not engage in anything remotely abusive. We would never, ever, say anything mean to SIL ever. We would never, ever, hurt SIL or her wife or their future kids. We would never, ever, do anything to harm SIL, her wife or their future kids. We love SIL. We would never say anything to make SIL or anyone else afraid of us. We treat everyone with love and kindness. We would never treat anyone that way.