Pretty confused, what do I do?

I have been dating the same man for all of my adult life (I am now 24) but I may not be in love with him any longer. I met someone else and started seeing him on regular basis, and eventually it turned physical. I know that it is a selfish thing to do even if we aren't married, but I didn't feel an ounce of guilt..nor do I to this day. He has put me through a lot and I have dedicated my whole life to making him happy only to have that taken for granted and not reciprocated. I am not trying to justify my actions though, they are wrong and they are my burden to bear, but I almost want to get found out so that he can be shaken out of his lull and complacency..but he doesn't even care enough to probe where I go much less, if I am seeing someone else. I need to know if it is a good idea to come clean or keep it a secret, end it with my current lover and try and resume/rebuild some type of relationship. I know if I told him it would come as a shock because I am more than sure he thinks I am so predictable that I'd never do this. I do care about him and I worry that my recent resentment towards him is only a by product of my other relationship, and if I was to end it with the lover I'd be able to put things into perspective and work it out. Any input is appreciated.