I'll add my two cents since I can't tell if
>>2 is being serious or not– the hell do you mean get rid of her? lmao this isn't a movie. There's no way to subtly try to break up a relationship. To me trying to do so seems immature and needlessly malicious. I wouldn't be surprised if it ended up just creating more drama that you might regret later.
If they really want to date each other, let them. If the guy really liked you that much, I don't know why he would be so quick to date someone else. (Literally the next day? Come on.) Unless he's trying to make you jealous, which would be very gross and manipulative of him. If I were you, I'd let him go and wait to find someone who respects your emotions and the pace you want to go at.
If you end up deciding you want to date the guy, do it as honestly as you can. Just tell him how you feel, if he doesn't reciprocate anymore, leave it be. Again, I'd advise trying not to be malicious about it.
The only ponit from
>>2 that I'd agree with is to clean up your friendlist. If she knew you liked the guy and dated him anyway, that's pretty messy. I understand going after what you want, but I couldn't imagine doing that to a close friend. Not necessarily saying she's a bad person, but she doesn't value you as a friend as much as it might've seemed before this.