The question of is it love or is it lust is an old one applicable to both straight and gay. We're human. Our emotions are not exact, but fall in ranges affected by everything around us, including hormones. This makes it difficult for either party to a romance to properly gauge the validity of their feelings, leading to emotional confusion. This is a simplistic reply, but am having trouble finding the right words.
Yes, I can fall in love w/ another man, and have a handle on the percentage of love vs. lust. However, I will only be able to experience this from afar, in my mind or only in a brotherly way, due to other obligations and duties. Life (and many kinds of love) are endlessly complicating my odd little world.