I slept with my coworker last night. I feel guilty.
Was it worth sleeping with your coworker?
The sex with him was good and I feel good about breaking the rules
Mixing love and work is difficult, because it involves your co-workers, your boss, and your career. Getting over your guilt will be more troublesome because you have to face your coworker every day, so talk to them and communicate so that you are on the same page.
I can't be bothered to talk to him about it, I just feel guilty.
You are not worried about the rules or do not feel the need to talk to him, I am wondering what you feel guilty about.   You should work through that guilt so you can continue the job.