My sister hides her boyfriends from me and I don't know why!
Update: I talked to her. She told me she kept it from me cause she doesn't want me to judge her or take her boyfriend's side when she asks him to buy her expensive gifts. They were arguing about this issue cause her boyfriend's income isn't enough to buy those gifts all the time. In the past she expected her boyfriend to constantly buy her expensive things even though he couldn't afford it and I told her it wasn't fair and that he "isn't her credit card". I still believe it's not fair but won't say anything any longer.
My sister and I are both adults. She is in her late 20s. I never ever know when she is dating someone because she hides it from me but all her friends know. She doesn't think I will try to break them up or snatch him , so I really don't understand why she keeps this from me. She dated her ex for almost a year and I only found out AFTER they broke up and by ACCIDENT! I heard her talk about him with her friend and confronted her. At first she got nervous and denied it but then she admitted it. That was several months ago. I told her many times that this made me feel betrayed , specially that all her friends knew and she told me she won't do it again.
Today she went out with her "friend" but came home early. I thought it was suspicious cause when she goes out with friends she never comes home early. When I was passing by her bedroom I heard her talking to a guy on the phone. They were arguing. It was obvious the guy is her boyfriend! I have no idea if it is her ex she got back with or it's a new guy! I didn't confront her this time. I still feel very shocked and numb! I can't believe she has done it again. I really feel betrayed. I don't know if I'm overreacting or not. I'm starting to develop trust issues. I feel like I don't even know her. We always have been very close and told each other everything, or at least I thought we did. When I am dating someone I tell her everything in details , probably because I am an idiot. Do you think I am overreacting? Is this normal behavior? Why would she do this?
Edit: I didn't put everything in my post so I say it here. My sister has double standards. She has different rules for her and different rules for me. If I don't tell her about my private things she will get mad at me but she never tells me anything about hers. She has all my passwords cause "we are sisters and should know each others passwords" she gave hers to me but immediately changed it. Our relationship is very unbalanced like I take care of her when she is sick but she never takes care of me when I am sick. Once she left me to go to a party when I was very sick, later my mom found me unconscious on the floor and took me to the hospital.
She gets mad if her friends pay any attention to me like once one of her friends who was my schoolmate followed me on insta, when she found out she got mad and told me to block her. She has never allowed her friends to be with me in the same room. Some of her friends think there is something wrong with me , a few of them even thought I am mentally disabled. I don't know what she has told them about me. She has lied and made up many stories to keep me from seeing her boyfriend and friends.
She pretended to be single and asked me to find her a good boyfriend while she was dating her ex. She has told me several times that when she marries she doesn't want me to be more than strangers with her husband cause "it's her husband, not mine" but when we talked about when i get married she told me that I should bring her to my honeymoon and it's okay cause she will be in another room. She also always expects me to bring her to all my friends' gatherings, events and vacations. If I don't , she will get mad and defensive.
I felt betrayed because the last time we talked about this she told me that she will never keep such a thing from me again and said I was her "person" , whatever that means! Yet she did it again! And lied left and right. I feel like I am an idiot!