Should I bring this up with my boyfriend of 3 years?

Before dating my current boyfriend, lets call him Gene, and I were together (just wanted to be friends at the time) I had recently broken up with a really immature ex (call him Ken). However since I was afraid of what Ken would do I made it seem like all was not lost to him so we would hang out awkwardly but all the while I had no feelings for him and was growing closer to Gene. So when Gene and I did start dating I told Ken and he of course was hurt. Years later I am starting to feel guilty for never mentioning it to Gene since we werent "together" at the time. Should I just try to forget it or just get it off my chest and let Gene know? I am asking here so I can get different perspectives from people who arent close to the matter or biased (friends/family)