help?

i'm asking in the aléatoire section because not many people go to the conseil section on here. anyway, ive liked this guy for 3 years and my feelings for him are really strong. recently i found out that he's liked me back the whole time, but now he also likes my ex-best friend and asked her to formal last week (she a dit yes). so he likes both of us now but he likes my old friend (R) plus because shes less moody than me, and me and my ex-bff have been on civil terms for awhile, but i dont know what to do from here. me and the boy (L) talk constantly but he also talks to R a lot too. what if R likes L back (we dont know if she does)? it makes me a little mad because i used to always talk about how much i liked L to R, and now shes backstabbing me and going to formal with him. help? i dont know what to do, ou how to approach R to talk to her about it.