How can I let my friend in without becoming a burden?

[TheCourtGemini13]

Hi, I'm new here, so before I begin, I apologize if I ramble. I have dealt with Anxiety and Depression for at least 15 years due to surviving mental and emotional abuse both as a young child and an adult. I have a friend I have known since I was 13 & met when I was trying to get out of my first bout of Depression. He helped me pull myself out of the Depression, and even though we would bicker, tease & act like 5-year-old's when around each other, he became my friend and I ended up falling in love with him, but he didn't feel the same way. We reconciled a couple years later but didn't speak for 7 years after due to college, lives moving in different directions. We then connected online and have talked sporadically since, until over a month ago. I was going through an Anxiety spell, and I ended up messaging him for spiritual advice. He surprisingly responded, and said if I needed to talk to someone, I could call him and talk, but as a friend only (same on my end, the romantic feelings have been gone for over a decade). I'm glad I can count him as my friend again, at the same time I'm scared to let him in because I'm afraid he's going to run once he knows what I've gone through. I want to tell him everything, but he's such a good person I don't want to be a burden. How can I let him in without burdening him with my problems and poisoning this friendship?