yes your wrong for cheating...if you dont feel that he is not doing what you want in the bedroom move on and tell him why keep him in the dark...if you met 4 times with the other guy you must not feel too bad...all me look dont try to find an excuse "looking is not the same as cheating" move on without him..but dont keep him there if your not satisfied..
Since you don't have a commitment with this guy, and it doesn't sound like there are any children, you are completely free to break up with this guy and have sex with someone else.
You're also free to tell him you want to have sex with other guys, that you no longer want to remain monogamous.
I really don't see, since you seem unhappy in this relationship, what the problem is with just breaking it off and starting over. Have you bought a house together or is there something that's keeping you there although you're not happy?
Well, cheating is wrong. Leave if you are unhappy but don't cheat.