This is horrible.

This a forum for support, so please forgive my blunt statements because I get that, but what you're asking us to do is very difficult.

You say you want us to give you advice to overcome this problem, this addiction you have, but what you're asking us to do is look past the 20 times of cheating, the fact that you don't want her to dump you despite of that, and you're surprised no one is giving you advice to solve this problem that is 100% pure selfishness?

You like the rush of cheating, but you also like to come home to your girlfriend. Men like you are my worst nightmare, sorry, but it's true.

I think you need to sit down and be honest with your girlfriend like others have said. You're scared of her dumping you, but how can you go on like this?

My advice, if you REALLY want to salvage this situation is to tell her EVERYTHING, and say you need and want therapy and go TOGETHER. If you work together to solve this as a couple, that is the only way to salvage this situation, and it starts with honesty.

Come on, dude, do the right thing by her.