I'm a serial cheater
Why do you continue to cheat?
The same reason all men cheat on their spouses, their spouses were not enough for them
You shouldn't cheat on your partners. If you feel this need all the time, then maybe you can be more clear about what you need in a relationship. That way, you won't be dishonest and can have a relationship where you both understand the level of commitment.
I get all the sex I need and even without a girlfriend I have fun
Well it sounds like you are more interested in casual dating and hook-ups than in having a committed relationship.  If this is the case, then I think you owe it to yourself and to your partners to not lead people on into thinking that they are in a long-term partnership.  As long as you are honest with people, some of them will agree to have a fling with you.