If you never interact with her again, intense thoughts of her will leave eventually. Time will heal a broken heart. Time will not heal regret.

To stop thinking of her because other people telling you you should stop pursuing her or stop thinking about her, that does not work. Just like you can't decide what you dream about. All you can do is for the actual choises you make is to make them all so it help's you forget her quicker.

May be a very long time. Some people claim they can fall in love with someone else and that helps them forget. I can see how the idea of having more options can help or can be soothing, and you definitely need to maximize interactions with the right type of females to increase success. But I don't understand how a person that is in infatuated with person A can become infatuated with person B. The first infatuating has to stop first.