FTM likes straight male friend?

Ok, so I consider myself trans. When I go out, I always wear a binder and I always pass as a male. I usually hang out with the same group of friends. 2 guys and this girl (Fred, Bob and Sarah (fake names btw)). They are all straight. The girl is married. Anyway, lately, I've been having feelings for Fred. He is a great guy but he is in love with Sarah. Nothing can happen with them because Sarah is married (but she leads him on, f*cking whore!). I always tell him that I like him but it's more of in a joking way. None of our friends would ever believe it because they think I'm all for girls. Can't really blame them for thinking that. And sarah is this blond haired blue eyed beautiful girl with a killer body. Most guys like her (ugh, kills me the way she treats her husband and acts like it's all innocent). Well, what should I do? I'm totally not his type. I look like a freaking teenage boy! But I do like him a lot! Oh and also, what should I do about Sarah? She always ask me to lie if her husband ask me any questions about where she has been yet she complains all the time about how much of an *** he is. But all the guy wants to do is hang out with her instead of her hanging out with us 24/7. He's an army officer and works all day, Just got off deployment 2 months ago. And we 3 deployed together and just got back 4 months ago. Fred, Sarah, Bob and I were together a whole year and Fred and Sarah spent way too much time together over there. No sex though. so HELP!