How can I make him fall in love with me?

So I've got this friend who's called alex that I've known for over 5 years,I was 8 when I met him and I had this huge crush on him. We became friends because we practice the same sport and he's 2 years older. He has a gf since November and it pisses me off. I told him the exact same day he started to date the girl, that I really loved him except I didn't know they were going out.He then told me and explained that it might happen one day, and that he really loves his gf... his gf's name is Patricia and they both go at the same school but I don't so I see alex 2 to 3 times a week. He told meback in december that I was a really special friend to him. and this Sunday, he told me that without me his life wouldn't be as fun. he also said that if one day I die that he would seriously miss me. I don't know if he likes me but I love him and I want himto start going out with him really. so how do I show him that he needs me?How can I make him fall in love with me?
Firstly, I think that if he is still with Patricia, then you shouldn't do anything about it, because Alex doesn't have stronger feelings for you than Patricia and it wouldn't be good to wreck their relationship because that's pretty selfish.

But, if he and Patricia have broken up, then you just have to continue being yourself and perhaps give him some hints.