This is a lesson to not cheat. Hopefully it makes you a better person in future relationships. On a side-note, if you feel the need to sleep with different people, be single. When you're ready to settle down into a relarionship, be ready to commit.
It is important, the spirit of repentance that you mention. yes, you made a mistake. A big one. But, my friend, remember. With Repentance, there is Grace. Grace is this thing that knows that you done fucked up, but is able to say, Try again. Grow. Be better.
You will be torn down for what you've done. It's inevitable. But this thing called Grace is there to build you up. It overlooks your errors. It sees what you're capable of instead of where you've been.