I want to fight my boyfriend sometimes
Why do you want to fight with your boyfriend?
I love him so much, but I want to have sex with other men
You should be considerate of your boyfriend's feelings. If you want to have sex with other men, you should discuss that with your boyfriend. Fighting with him about it will only lead to conflict between you two.
I think I just need to do what I want. He won't understand me.
If you don't talk to him, then you're not giving him the chance to understand you. You should try to be more considerate of how he feels. Think about how you would feel if your partner decided not to talk to you because he assumed you wouldn't understand him.