My boyfriend left me for his "best friend" somebody please help, I am so heartbroken?

Anonymous
So I dated this guy for 3 months. We had a very strong emotional and physical connection. We spent LITERALLY every day together and we made a great team. He would always tell me that he's never felt this way with anyone, that I made him feel alive again and I've made a positive impact on his life. All of his friends and family loved me and accepted me as their own. They thought we were good for each other.
Except for one of his friends who was always rude towards me. She is a female. They've been friends for 14 years and claim it's always been platonic.
Well eventually we ended up breaking up because of a couple problems of our own. A day later he's in a relationship with her.

I talked to him about it and he said that the reason he's with her is because it's "safe and comfortable, but he's not really attracted to her and has no affections for her... she's just comfortable"

Now I am entirely hurt by this because he swears that his feelings for me were true, but now he's dating HER? I am so hurt by this and confused.

I should also mention that he went through a divorce earlier this year, so he's still scarred from all of the hurt he went through which probably has something to do with it.

Can anyone please give me their input as to what you think is really going on here?
My boyfriend left me for his "best friend" somebody please help, I am so heartbroken?
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