So, I have a boyfriend.  I have been with him for 6 years now.  But I have to be honest, while we have stuck with each each other though thick and thin, I secretly have never really liked him.  As a person or sexually.  There’s a lot more to that story, but the one I’m trying to figure out right now is my straight friend.  Let’s me just get this awkward bit of info out of the way.  He’s 19 and I’m 31 (generally people think I’m in my early 20’s though)  I know, sick I’m too old for him.  I am indulging this info though because maybe I just don’t know how young guys are these days.  But it all started at school.  I spent a long period of my life in the military so I got started in school late.  We ended up as lab partners, and even though I found him annoying at first, we really hit it off.  We spent all sorts of time between classes, he a couple times just attended my classes just to spend time with me, and he would touch me like so straight guy has ever done.  He even like just started touching and very carefully playing with my elbow one day, while I just pretended not to notice.  (But I liked it ALOT) After school, we would just hang out in each other’s cars just talking for an hour plus.  It took a while for me to tell him I was gay and in a relationship, it was awkward for like a week after that.  He did say though that me and my boyfriend should go on a double date with him.  While he’s pulled back since then about some things, at the same time he’s doubled down on others.  We text eachother at times I would never with any other straight friend.  Till like 2am one night.  He always wants to bring me lunch when I’m in class, I always decline, but he usually saves a good part of his lunch for me when I get out of class.  He sits a little farther away from me now than before I came out, and there is less touching (I still make myself available to be touched though). Things are just weird I’m so confused.  I’ll notice out of the corner of my eye he’s stairing at me, but when I look or try to get his attention it’s like I don’t exist.  Or when girls around he’s just a flirting machine, and once again I don’t exist.  Just standing there by my lonesome waiting for my turn again lol.  Oh, I forgot all the times he’s walked me to my car, even though it’s super out of the way for him.  That’s just not normal behavior for a straight guy.  Many of these things aren’t normal, but at the same time, he seems to have zero interest in anything more.  I’m just super confused and would appreciate anyone’s thoughts on what might be going on in his head. 

Maybe he's acting that way because he likes you and at the same time, he does not like it that he likes you. You're saying that he's straight, but what if he's not? What if he's confused? (If you know what I mean)

This attraction between you two makes him realize something about himself and maybe he just doesn't want to admit it to himself. That is why he flirts with girls, and tries to be indifferent around you because he is still figuring out what he really feels. This is just a MAYBE, alright. But from what I got upon reading your post, that's the message that I got.

Here is my advice: I think what you should do is before you punish yourself with thinking about this friend of yours, figure out first what you feel about your boyfriend. Assess your feelings for him and decide whether to strengthen your bond (your attention may be too focused on your friend), or to end it if you think it's what's best for the both of you. Do that first. Whatever it is that you chose, it shall help you decide on how to deal with your friend.

Good luck! Hope I helped.