I have a girlfriend, but I constantly look for hookups on dating sites.
Why would you do this to your girlfriend?
I want to have a break from having sex with only her.
Cheating on your girlfriend and hooking up with other people is immoral and you are being selfish and wasting your girlfriend's time. End you relationship so you can both move on and be happy.
I thought I love her, but I don't know for sure. I think it's just an obsession now. I mean, I have to have sex with a different person everyday.
If you don't love her anymore you can break up with her. It would be better than to cheat on her, it would hurt more to be betrayed like that.