Was my friend being arrogant? (Pleaseee answer me :( )?

Sorry, but, she has the right to any boy friend she wants. You should not interfere with her romance. Her boyfriend should be her business, not yours. You asked for what you got and there is nothing for you to get back at. You now need a new friend because that one is gone. Sorry but you need to learn respect for other people or you will always have problems.