I'm overracting or should I be really worried about my boyfriend's female friend

Hi, I really need advice on my current relationship - I will be grateful for any comments, because my head is a mess and I don't know what to do. In short - we are together for about 1,5 year and live together for almost a year. My boyfriend is younger than me - four years younger and I'm 24 years old. He was always supportive, we have a lot in common, but somehow I don't feel somehow secure in our relationship. I am especially worried about his friendship with one girl - I'm not jealous or controlling type, and I would never ask him to stop seeing his friends or choose between them and me, but she makes me uncomfortable. Here a few examples why: - he knows her longer than me, when we started dating they knew each other for about a year and were really close. They talked about everything and he used to sleep at ther place sometimes. However, when we started dating he claimed that there was nothing beside friendship between them - they were not interested in each other romantically or didn't sleep with each other. He was the one who introduced her to me and at the beginning I really hoped that I and that girl will become friends, because my boyfriend said many good things about her. But she didn't seem to like me. From the beginning I felt like there is some kind of competition between us, she tried to prove to me that she knows more about my boyfriend than I am and concentrated only on him, ignoring me during our meetings. She would sit next to him all the time, and asked him to go for a cigarette alone to talk etc. It was not easy for me, because I saw how my boyfriend seems relaxed and how good they get along and I became a little jealous, especially that his female friend is really attractive girl. I didn't show my jealousy, but I started questioning why he would choose me over her. - Then, there was a party at our apartment and she was invited along with some other friends. I was surprised, as she never (as far as I know) was at our apartment before, but she started to make comments on new furniture ("The shelf was the only thing that you bought for that apartment, everything else was already there?") and I got strange feeling that she was there before, but maybe I was overreacting, because she said also that we have lovely apartment and my boyfriend went down for her, as she didn't know the exact way to our apartment. Furthermore, my boyfriend claimed that he mentioned to her that he bought some things for our apartment and she was never there before. But I started to be wary of her, as she turned to be manipulative and I didn't exactly know what her intentions with my boyfriend really were, so she could just put a impression that she was at our apartment for the first time. - I was also worried that my boyfriend deleted all his messages from her (I found out by accident, when he was showing me some pictures from her and there was only a few messages from the last few days). He claimed that he knew at that moment that I'm jealous of her and once (I know, I should be ashamed) I read few messages from her behind his back and confessed to him about it. I violated his privacy and he was really mad, so he deleted all messages, so I would not snoop again, especially when I was jealous of that girl, and I would misunderstand some messages, as my boyfriend claims, and he would rather avoid that kind of situation. But again, he claimed that there was nothing between them and I shouldn't worry about there deleted messages. - There was also a few nights when he slept at his friend's place, when he and his friends had too much to drink. I thought it is ok, since it was more dangerous for him to walk home in his condition, so he was coming back next morning. But there is one night that I was especially worried of, when he fell asleep drunk in his friends' bed and there would be nothing suspicious about it, except that female friend claimed that she came to the room where my boyfriend was sleeping in the middle of the night and tried to wake him up, because "she was worried if it is ok for him to sleep in other place than his place". My boyfriend doesn't even remember if she was waking him up, he only remembers when he fell asleep and when we woke up and went to our place. But knowing her, I wouldn't say that she was suddenly so worried about our relationship or whatever, and she had other intentions in waking him up. I wonder if something happened between them back then, especially as she teased him if he don't really remember the moment of waking him up. My boyfriend claims that nothing happened, and he wasn't that drunk to not remember if something happened, he was just really sleepy and thus doesn't remember when she was waking him. - Last thing, it is also situation from a party that we attended. I forgot about one thing - my boyfriend and that girl have no longer much contact, as she turned to be bad person, and my boyfriend claimed that I was right about her from the beginning. They sometimes see each other at parties, but beside that I believe that they have no contact. And now, she is even worse than when I met her - she has a boyfriend and still have many one night-stands, she already slept with almost every guy from their friends' circle, she is really provocative and my boyfriend claims that he is sick of her promiscuous behaviour and that she doesn't care if someone gets hurt, as she seduces even taken guys. To the point - we went to the party and I got really mad at her, and how she behaved around my boyfriend. He tried to ignore her, but she was laughing loudly when he said something funny or not, tried to touch him "accidently" many times, but I found especially disgusting her gestures - when she knew that he is sitting next to me and sticked her butt almost in his face when she tried to open the window (and it is not my imagination, someone else claimed that her behaviour and gestures were slutty and it was obvious what her goal is) or other time she "accidently" dropped something on the floor and she leaned to lift it in a really sexual manner - my boyfriend was sitting in front of her, and she spread her legs as much as she could when she leaned across and was looking directly at my boyfriend as it was some kind of invitation? I know that my boyfriend was trying to ignore her, but later on I felt sick and asked my boyfriend if we could come back earlier, because I'm not feeling well. He took me back to our apartment, but was really mad that we had to leave earlier, as she wanted to spend more time with his friends. But I started being worried that maybe he wanted to come back to that party because of this girl? Maybe her obvious flirty behaviour made him want her, because she is really attractive and many guys are attracted to her, so why if my boyfriend likes this kind of behaviour and likes his interest in her? I really don't know what to do, I'm uncomfortable when she is around my boyfriend and I'm afraid that she will seduce him someday. I know that he doesn't seek any contact with her, and he claims that I shouldn't be worried about her, but somehow I am. I want to trust him, but isn't it all a little bit strange?

Hi mutedlandscape, I don't think you have anything to worry about with your bf. I think you can trust him and believe what he's says. He introduced you to this friend, he talked to you about her and you knew about her from the very beginning(?). If he was cheating, etc, he'd be hiding her from you - I learnt this not too long ago when a girl started hanging around my bf at uni (she's not as bad as your bfs friend), they did lots of things together, he's was five hours away so of course I was worried! So I do understand how you're feeling and I'd say it's justifable. There is a lot of jealousy going on her part. she might of had feelings for him for ages but maybe he's only seen her as a good friend and doesn't fancy her. When you started going out with him, the dynamics changed, their friendship went from two to three, it was going to be different and she wouldnt get alone time with him. Hence the private conversation whilst smoking. She was probably never going to like you (no matter how nice you were to her) or any other girl because she wants him to her self. With the deleted messages, maybe he was just annoyed and wanted you to trust him, I'm not sure,but I don't blame you, you needed some reassurance. Her new boyfriend - she's probably realised she not getting anywhere with your boyfriend and the new one is a kinda a replacement, but it's clearly or working out if she's cheating on him and sleeping with lots of other boys. it does sound like their friendship is fizzling out slowly. You mention you bf was getting bored of how she was acting , he even admitted you were right about her and he had less contact. He's starting to see the real her. At the party she was probably angry which could explain the sl*tty gestures (attention seeking). It's pretty sad on her part, she's clearly unhappy. If other people noticed how she was acting and found it annoying , then it's not just you and she's not doing herself any favours by being liked by others. not a lot people would like the way she was acting. Your bf being annoyed about having to leave the party, I think he (wrongly) took it out on you, you were the closest person to him. He probably just wanted to go out and have a good time with you, he probably didn't like the fact the girl was there and she ruined it for him (and you) and made you want to go home. She succeeded in a way. I think maybe steer clear of her as much as you can but it's her problem really. I hope this helps.