Love triangle :(

I got out of a 4 almost 5 year relationship some time ago and we both decided we should be friends. To this day he still has strong feelings for me but i just really care about him nothing more. Lately someone that he is close to and I have been spending a lot of time together and have grown to like each other tremendously (the attraction was always there just never acted upon). I can honestly say I felt like I was missing out on something wonderful because I was in that relationship with my ex. Well this guy is feeling bad now because he doesn't think it's right and so we decide to cool it and make it known to my ex that we like each other but we weren't going to pursue anything just to spare his feelings. It's a serious case of my ex is looking at me while I'm looking at this guy and this guy is looking back at me kinda thing. Anyway my ex keeps complaining how he doesn't want me to hate him and feels I'll eventually get that way if he don't let us be together... I really want to be with this guy eventually but not at the expense of someone else...I honestly don't know what to do.....it's tricky