MADLY in love with straight best friend - don't even know what to do anymore

Before I begin, this is a VERY long story, and I would really appreciate Long responses, as I'm really starting to lose hope.. It all started when him and I started playing VIDEOGAMES a lot last summer. He would invite me over for sleepovers and he would be a really good friend towards me, especially because I had just gotten out of toxic friendship right before last summer began. After the summer, since we were in the same class, we became even more close during the school year, until in December when I realized I ha started to develop feelings toward him. I forced myself to repress the feelings , because I knew it wouldn't turn out good if I came out to him, (which I was definitely too scared to do back then) It worked pretty well until March came around, and I was actually starting to miss him, and it wasn't just a small crush which I thought it was back in December. We had became best friends at around March, which is when he told me had a crush on this girl (Let's call her Bee) He was OBSESSED with bee, but still, I suppressed my feelings because I knew it wouldn't turn out well , and I realized that if I let my feelings get in the way, then the friendship would be ruined. And as the months went on, my feelings grew towards him, and I started to begin to be angry towards him and start small fights with him. Some of them were because deep down I was angry he didn't like me back, and other times it was because he wasn't being a good friend (sometimes abandoning me) however, he's really blind when it comes to social behaviours , meaning he acts without thinking sometimes, and doesn't realize that if he ignores someone for awhile, that it hurts. Fast forward to July, and he gets his first girlfriend. I was heart broken, I was so depressed, and I cried at the darkest moments, when he would drag on about how she was so beautiful. I envied her, and I wanted to be in her shoes. He
would also blow off some videogame sessions we had for her, which only added to the fire. They broke up after a week, and everything was pretty good for the next month. Last week, I even gave him a handjob, and we pretended to have sex. He also have me a handjob , bu it because I initiated the first handjob I gave to him. And I know, that doesn't seem too "straight" but I only managed to after going step by step and slowly easing into the hand job (meaning I didn't flat out just pull down his pants and go) Also, he always talks about girls, and I even checked his history and it's all about girls. (I know, that's creepy, but I just can't help myself) Besides the sexual roleplay and the handjob, I don't see any sign of him being bi. So my problem now, is that he likes another girl. Which again, made me absolutely heartbroken inside. I realized last night, that this can't go on anymore. But he really does make me so happy. I can't bear not being able to see him or talk to him. That's why I can't forget about him, or cut the friendship off. However, I finally realized the truth last night, and saw that he's absolutely straight, and that I have no chance. He'll be gone until the first day of school, and I don't even know what to do anymore. I wanna forget about him, but every time it think of him and his new crush, I start to feel depressed. My plan is to tell my feelings by the end of September. He's also homophobic, but I don't care. I can't let this go on anymore. I'll tell him the entire truth, so that I can finally relieve the bottled up feelings , and actually move on from this guy. And if he lets my sexuality change things with us, I know I'll be absolutely devastated, but it's the only option I think I have. Which is why I want to ask you guys, what should I do? Because I don't even know for myself anymore.