Help??!

I'm pansexual (sexual attraction to all genders), just in case this story might confuse anyone. 
My best friend of last year ended up becoming my girlfriend (she's gay), we were friends for a year and dated for nearly 2 months. She broke it off in December because I wasn't handling my depression properly and putting all the pressure on her.
Fast forward to now, and i have a boyfriend of 3 weeks. Her and I became friends, which i found was a big step in getting over her.
I recently went on vacation, and as the trip went on, I missed him less and her more. I thought all i wanted was to be friends with her again, or to feel wanted again. I'm really not sure how to tell him how I feel, and I don't want to hurt him in any way. Any suggestions??
((sorry for the long ass question btw))