I'm torn between two people....but wait there is more...

Wow....where to start. Well I'm a 28 year old male in a LTR and I thought I was straight. I have gay friends and lesbian friends and I have never hated and have always loved them for their sexuality. You do you, I do me, and as long as there isn't any negative it's cool. I like that people have different tastes. Always thought I was straight. Nothing wrong with thinking you are of a certain gender preference. Well a few months ago I met this guy who's a little you get them me and my gf (my gf is 4 years younger then me) he's 20. He is the best guy friend anyone could ask for. He's an outdoorsy man who isn't afraid of dirt but he's gay. He is the straightest gay man ever. We can even talk about how hot chicks are and I'm an ass man so it's great that he's one too and we can comment together, he drinks beer and likes to play video games. He is the best friend I could have ever asked for but lately that friendship line is a bit blurry. Me and him fooled around one night. In not going to lie, I liked it. I liked it a lot. The thought of fooling around with any other guy has me all weird and grossed out but the thought of him is something different. The worst part is that I put him in the "other person" situation and I have not come clean about it to my girlfriend. That's ok he said he's been the other man before and it doesn't bother him because he lacks morals (his words) and he is close to my gf so he doesn't want anything to happen. Since then we have kind of just let go of a lot and we kind of cuddle and hang out half naked and shit.obviously in front of my gf who doesn't wear much on a good day anyway so she isn't weirded out and she knows that both of us have shared some intense and slightly fucked up emotional problems together and that we are really close so she doesn't think anything of it. Well I do now. After we started to let go I started to want to let go more. I love the way he feels when our skin meets. It's like electricity and I can't stop wanting to just rub every inch of me on him just because I love the way our skin feels when we touch. He is in looks department what I look for in a woman, lighter hair and blue eyes, nice shaped butt and long legs. He is a lot like my gf in appearance and attitude as they are the same horoscope sign (which is highly compatible with mine of course) and I'm thinking maybe my attraction started when I realized how much he is like my gf. I was worried I had fallen out of love with my gf but that same electric spark feeling I have with him is what I have with her and I have always felt it. That's what makes this hard. I can feel the physical love between me and my gf and I have that same feeling for him. When we kissed, me and him, it literally felt and tasted like my gf. I know I'm his "preferred" type and that makes it harder. I love him so much my heart breaks when he isn't around which is a lot because he works aloooot. But when I think of not being with my gf I have that same heart break feeling. I can't figure it out do I want him or her, and I wish with all my heart I could have both but I don't think either of them would be I to it as much as I am. Not only is there this who do I choose how do I live with loving two people, but I am also still struggling with the fact that I have feelings, sexual and otherwise, for a guy. I have never felt like that. Questioning my sexuality while going through this is beyond what I can deal with. The sad fact is when I think of how easy it would be for me to deal with this if it was two women I don't even think I could ever do anything with another woman behind my gfs back. I know I fooled around with my best friend but I can't even compare he two situations because I jnow kn my heart this would not have happened with another girl. The chance has been there because I have been hit on a lot in my relationship and I have never even liked the idea or entertained it. If anyone can help me feel even a shred of sanity in this situation I would be so happy. The cheating isn't even the part that bothers me the most, it's because I literally am very deeply in love with two people at the same time and I can't grasp it. How is it possible and to a guy none the less. Please help me.