We have been in a relationship for two years, going out almost every day, neither I nor she have many friends, which is why we usually go out together.

She met a new friend (female) 10 days ago and they've been out 3 times in the last 10 days, which is something new to me.

She told me today that she had made an appointment with her again for Friday, but what is controversial is that I wanted to go out with her on Friday. We started a fight and I said I guess I should have some privileges and that we should go out when I want to, not when that friend she knows for 10 days wants. What to do?