My best friend has just gone out with my X?

She knows I have a soft spot for him and hes special. We are a group of friends. She hasnt even consulted me about it. Shes not even thought about how I would feel. How can I tell her indirectly? Also before we liked the same guy at the same time but he liked her back. Of course it was hard for me but it was also hard for her because she wasnt going to go out with him because I liked him. In the end I pretended I liked someone else and made those to get together because I felt bad. I didnt want to get inbetween them, the relationship was a fail though and didnt last long and I kinda feel like an idiot for letting them get together if her feelings were just a one off thing? Im hurt shes not concidered my feelings on this. What do I say and do?