Saying fuck you to my girlfriend?

My girlfriend and I are fighting bad. I didn't call her names or anything but i said 'fuck you'. At some other occasion i say 'fuck off'. I think its perfectly Normal. But she said i was being disrespectful and always told me to stop talking to her like that. Its not just me. When we fight she says 'fuck you' too. So i need your oppinion, especially girls. Was I that bad? Was it normal? Thank you in advance
Saying fuck you to my girlfriend?
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