Do I have a right to be mad when my BFF ditched me for her soul mate?

I recently introduced my (new) best friend to a guy friend of mine, and they had casual for a while before he gave in to her advances and professed his undying love for her. For a year before the day he said "I love you" she had spent at least 3 hrs a day with ME. Within 24 hours she was pretty much out of my life. She completely stopped calling, texting, etc, and when I call her, she goes on and on and on and on about HIM. She breaks plans CONSTANTLY and I try not to say anything because I'm no idiot; I know how this works. But when I finally gave her grief the last time she broke plans and tried to express how I felt (in a very diplomatic, non-guilt trip way might I add-I don't want all of her time, I just want the word "best friend" to actually MEAN something), she told me they were in love and getting married and if I couldn't handle their happiness then we shouldn't be friends and "why would I want to hang out with someone that only gives me constant guilt trips anyway?" She apologized, but this bff-ship surely is no more. I'm just wondering, who is right?