what to do if your boyfriend dumps you for your friend?

I would try to talk to them about it. Especially if you're really hurt, it is good to discuss it with them and see where it goes from there. From there, it can go 2 ways. You either get a satisfactory feeling from the conversation and then you can continue to be friends with your friend, which would be great. If the conversation does not go so well, it might be good to let it rest while you get time to think about the situation and figure out what would be a good way to move on from it.

Remember that people come and go in life. Everything happens for a reason. Think about the people who impact you positively, because they're the only ones that deserve your thought anyways! As far as your ex goes, they don't sound like someone who you would want to stay with anyways (as harsh as that sounds) and same for your friend. I know you're probably feeling angry and betrayed, but this only opens up opportunity for you to find a better partner and a better friend. You will look back on this situation one day and think "why was I even upset about those two". You got this. Keep your head above the water. WE love you!!