I think it's finally time for me to end it [Update]

So I(23m) met my gf(20f) back in march of last year and we had a great time in the start. I actually felt like I had a partner who loved and cared for me but over time on closer inspection I have found her slowly showing more and more red flags. She doesn't hang out with me very much anymore and I have caught her in multiple lies and manipulation. She doesn't want to do anything with me anymore aside from blowjobs and I don't even feel wanted by her anymore. I have tried to talk to her about it and I have tried to stay loyal and give her chances but come to think of it we were only sexually exclusive for like 3 months and up to that point she would lie about not having sex with other people and I know damn well she was fucking other guys while claiming to be faithful. I don't even feel like I'm in a relationship with her anymore. I have done every ounce of humanity to her and she has only used me for my money and my dick. She gets mad at me for not believing in her lies and I feel like I'm just a damn cashcow to her.<br><br>Could anyone please just give me some advice on how to properly end it because I don't want to hurt her but I don't want to feel used anymore.<br><br>Edit: Holy shit! I didn't expect this post to get so much attention. Thank you so much for all the advice and really useful comments. I'm going to go end it and go hang out with my boys.<br><br>Update: Finally ended it! Called her up and broke up with her and she doesn't even care! She was totally monotone on the phone and she said "ok cool bye" when I told her that I'm breaking up with her. I guess I dodged a bullet because really the only thing I'm feeling right now is relief and no sadness. Hanging out with my boys this weekend to get my mind of things. Will post more when I do. Thanks a lot for the help user.