What should i do about my relationship problem?

If your friend didn't tell you then she should suffer in silence. If she liked him she should have made a move, what were you supposed to do? Just assume that she liked him so you can wait for her to make a move?

I agree with Chris - it just sounds like she had unrealistic expectations in this situation and that's not fair to you. Beyond that, you have a history with him and I'm assuming she doesn't. On top of that, he's one of your best friends. I think your friend could stand to be a little more understanding here. It's one thing if she's just mad at herself about holding things in and wishes she had said something....that is understandable but if she is mad at you well it's just not justified at all. You didn't do anything wrong here. The ball is in her court as I see it. You can only do so much to salvage this relationship. A lot of this is on her. If she is a friend worth having she will find a way to get past this and understand.

honestly screw your friend, do what makes you happy.

I'd apologise to your friend, but explain that you had no idea she liked him and still want to be friends. Maybe keep the lovely-dovey stuff low key for a bit, out of respect to your friend.

I think that you shouldn't break up with your boyfriend. Your friend didn't tell you how she felt and you love him so she can't blame you for saying yes. If she is still mad after you give her some time to think you should talk it out with her and explain that you never meant to hurt her and tell her how you feel about your boyfriend.

@Rena-san I want you to know that I have to fight the urge to troll you so bad for your logic here!