I just had to break up with someone who is a serial cheater. He admitted to it, but doesn't seem willing to want to change, or doesn't think he CAN change.

Like others have said, you must commit to changing 100%. Get into therapy and address the root cause of the problem. Be honest from here on out with your wife. Perhaps do couples counseling together to help heal the wounds. Cheating leaves deep wounds and mistrust. You will need to build up trust again with your wife, and that begins with being honest, ceasing all contact with other women that are tempting to you, and committing to change.