I am leaving someone dear. How do I tell him what I feel?

Next fall I will be travelling all the way to the other side of the Atlantic and stay there for 5 years (and if lucky, forever). I will be coming back to my home country every now and then for holidays and such, still I am leaving many people behind. It's not like I am crying in my bed for abandoning all those who are close to me, on the contrary I am really excited about this new chapter of my life, but I'd like to express my gratitude to them for the moments, memories and help they have given me these past years. All of them know I am gay, apart from one person. Let's name him Peter.

So I and Peter spend a lot of time because we practise the same sport. In fact, he is my mentor in a martial art. He regards high of me, he thinks I am very talented, he considers me to be one of the best students he has ever had. I, on the other hand, am a very realistic person, so I clearly see all his flaws (as I do with most people): how he sometimes projects himself on me, how he can talk for hours teaching people about philosophy and life as he were transmitting his experience and wisdom to others, how much time he spends for our martial art and not for his family etc. But still, I feel really close to him, and I don't mind about his "flaws".

The problem is that we don't see each other at all outside of practice and I hardly believe we would have become friends if we weren't so often together at practice. I can't tell if we have things in common, if this is a true friendship or the outcome of me being kind, him praising me so much and us spending so much time together and liking the same martial art. We've known each other for roughly two years (from Sep '14), he is rather introverted so I always struggle whenever I want to know more about him and yet I feel very close to him. Whenever I think of him, I feel calm, serene, warm inside and giggly and I always look forward to my next practice session. Now don't go telling me this is love (love love, not just brotherly love), it isn't (is it??).

Anyway, the time for me to leave is getting closer, and of all the people, Peter is the one I want to thank the most.These past two years I feel like I have grown from a dependable, geeky student to a decisive, self-confident and versatile man and I think he has contributed a lot to that as he was the first person to ever praise me so much for something other than my academic skills (I get praised for that all the time) and helped me feel like an ordinary guy, as opposed to hard working gay guy who hangs out only with girls and has too few time for his personal life, which is how I see myself. I feel I owe so much to him and I am very disappointed and depressed thinking that I won't see him often. Because I feel we have nothing in common apart from the martial art, once I leave he will drift away and become just another acquaintance... I fear that I will return in Christmas and I won't have anything to talk with him about.

Uh, I am trying hard to write a concrete and legible post, but while I write it, I realize many things about myself too. My initial intention about this post was to ask how to I should come out to him without labelling myself as gay. But now that I have written the previous paragraph, it seems to me that I only want to come out to him because I don't want to lose him. So that when I return in Christmas, I will be able to talk to him about my personal life, my new experiences. If I can't talk to him about those, then I think I have nothing to talk to him about. And yet, even if this realization reflects the truth and I feel I shouldn't be a drama queen and not expose myself, I also feel really sad that I won't tell him anything about myself. I want him to know me, to know the real me, to know what I am thinking, how I feel. I'd like to know more about him too. I want him to become a really close friend. I want to hug him and thank him for everything, and to know that he knows everything about me and still supports me. I want to express to him all of my fears and hesitations, even about me being gay or not, and him answering back in his usual "wise philosopher" way to actually help me.

I am really sad because I feel there is so much great potential between us, but now I have to leave and I will never get to know if Peter would have become a special person (as a friend) in my life. I think that I think coming out to him will speed things up and will get us closer so that our relationship will endure the distance, so that whenever I return I will have someone to look forward to seeing again to catch up. However, I don't want to go all "I am gay, boohoo, let me blurt out all my problems so that you pity me and force you to comfort me as if we are close friends".

This post has been an emotional roller coaster for me, but now I realize that what I really want to do is tell him all of those things I have written. Then again, it's too much for an unsuspected guy to handle, how could I say all those? It's like a confession, he will freak out and I want to avoid that at all cost.

This turned out to be a long and incomplete post. I don't know what to write, how to conclude it. This is difficult... If you have made it till this point, thank you for bearing with me. Please tell me. What do you think? What do you think about my feelings? Should I talk to him? What should I say to him? Does coming out actually have anything to do with this, should I mention anything about me being gay?