Lost respect for friend after sleeping with her

M24. I had this crush on a friend of mine, F21. After telling her how I felt, she said she didn’t feel the same. I thought whatever but I was kinda bummed cuz I still liked her and found her very attractive.

After some ranting about it on an anonymous posting app, some guy gave me advice to be very cold, almost rude to her but keep her at arms length. I initially rejected the advice, I’ve always despised the idea of “nice guys finishing last” but I guess jealousy and my attraction to her made me want to try it. So I did.

I started waiting ages to respond to her messages, leaving her on read, giving very blunt responses, one word answers. I’d pretend to get annoyed at her but would keep engaging her with jokes and just telling her whatever I was thinking of when I decided to text her.

After about a month of this, we both ended up at a party together. I was the only person she knew there so she kinda clinged to me. I was still being frugal with my attention, at one point I put my arm around her. Pulled her close and she stayed there, it felt nice knowing she felt safe with me. I whispered to her “wanna get away from the party for a minute?” she nodded so I walked her upstairs.

We went into a bedroom, start undressing each other. She goes down on me, I pulled her up and threw her on the bed and fucked her. Admittedly I finished quite quickly the first round lol but the second and third we went for a while.

After we were cuddling with each other and she asked me why I hated her, I knew what she was talking about but I played dumb. She brought up all the things I had been doing, the messaging, the cold behaviour, etc. I told her I didn’t notice I was doing any of that and that I’ve just been busy. She then apologised for accusing me of it and we moved on. She gave me head one last time and we went back out to the party.

But ever since I’ve been thinking, all the time I spent with her before, all the cool nights and good memories I shared with her, the laughs, the deep moments when we start talking about personal shit. None of that was enough for her to see me being more than a friend but treating her poorly for a month got me laid? I started to genuinely want to distance myself from her. Partly due to the shame of what I did and lying to her about it but also like, have some self respect woman? I shouldn’t judge because I obviously come off worse in this scenario but damn.

TLDR: I treated my friend poorly for a month Dn got laid as a result