Depression Support Group
Depression is a real and debilitating condition that is often misunderstood by family and friends. Its meaning can range from a prolonged period of sadness to an actual mental illness with specific symptoms. Find and share experiences with others who are going through the same struggles.

Try to focus on what you said, that he loves you, and think about something else. Believe me I know how hard that is though. Maybe distract yourself with a book or something? Good luck. I hope you can get your mind settled down soon.
I am no expert in relationships but if you love and trust your boyfriend I think you should communicate with him how you feel about the situation.
You want to be able to trust your boyfriend just as he has trusted you so without accusations or assumptions as you welcome him opening up to you his feelings towards his long time friend is not only inappropriate but hurtful and tends to brings on feelings of insecurity leaving you questioning his faithfulness.
And as much as this might hurt a little reassure your boyfriend you only want to see him happy and if whatever or whomever he choses makes him happy then you are happy for him.
But no matter what try to remain positive within yourself and in your relationship while indirectly showing your boyfriend all the great attributes you have to offer and soon enough he'll realize on his own he made the right decision.
Hope this helps...