Should I retaliate to her?

You should definitely think before you say anything more to her. Just say to her that you honestly didn't know that she had feelings for him or else you wouldn't have pursued a relationship with Daniel. I think it's pretty unreasonable for her to ume that you knew and she should have told you before you got together with him if she knew you liked him too. Just tell her that you're sorry but you didn't know and that's not your fault. If she still has a problem with it then there's not really any more you can do except break up with your boyfriend and that's definitely not fair to you and a friend shouldn't expect you to do so either. If she can't except it then she should move on and the friendship may just have to end.