I dont know what Im doing.. Please help?

Im beyond confused. I have been with someone for 4 years. Of the 4 years I have been having a "friend with benefit" (FWB) on the side. The first year I was faithful and then that ended. I had huge feelings for the FWB, a guy that me and my boyfriend are cool with and he ended up moving into the same complex as me so it made it that much easier to start something with him. Things got really heavy. He told me he liked me and I felt the same but I was really into my boyfriend too whom I was dating so I couldn't let him go. We ended our FWB relationship for almost two years. Meanwhile we worked together for sometime and flirted like crazy and he would just give me this feeling that no one has ever made me feel. We both can just look into each others eyes and have the strangest chemistry. We started sleeping together again a few months back and I'm still with the same my boyfriend to this day. My BF and I fight like crazy and he has always treated me not so good but I cant seem to just let him go. My friend with benefits always told me that I will never leave this guy which also makes me think thats why he is acting this way. He knows I will only hurt him. Lately I have just been wanting the FWB so so much... I dream about him ALL of the time for years now. Every song reminds me of him, I cant get him out of my head, we have the strangest craziest attraction to each other. I ended up telling him how I felt recently, but he told me we could never be together because he is friends with my B and we all know the same people. It would look horrible on us which I understand. I let it go and kept sleeping with him so the other day I came out and said, "look honestly I cant stop thinking about you, If I really left him could there be something with us" and asked if he felt the same, he said "no". It hurt like hell! I told him I felt disgusted with myself for doing what I was doing and he had no feelings with me. I kind of let him have it and pissed him off via text. He was upset and I basically wasn't going to talk to him anymore. The next day, he texts me out of nowhere asking if I am going to be nice. I asked him why? and he said I was being mean the other day. I told him well you hurt my feelings but I understand you were being honest. He then said that he is just not a relationship type of guy. When I am with him, he seems so into me, like he really is crazy for me, but then again I know he cant be tied down( he never commits). Is he really serious and does not like me or is there a chance he does but he does not want to get into a relationship though. This has been going on for years. Why would he continuously see me and flirt and just look at me in my eyes like no one has ever done before but not like me at all?? Makes no sense!