[Chi]

I know this may not be the best solution but you said you shared this with your current boyfriend.
If you're too scared to tell him to shove off, ask your boyfriend to do it? I'm not doubting his care for you but if this is really bothering you, ask him for your help. Ask him to tell your ex to piss off.
If I asked my boyfriend for help on a problem like this he would either tell me what I should say to him or he'd do it himself. Sometimes you just need someone to help you fight this battle.
I recently had this kid hitting on me over and over and eventually I told him, "Look, I have a boyfriend, I'm not interested in you that way. My life is stressed out enough please stop texting me. Maybe we can be friends in the future but you need to give me space."
In your case I would just tell him to leave you alone, he's made it perfectly clear he doesn't want to be friends he wants to be more than that. Don't let him have that tell him you don't want him in your life anymore and if somehow you ever do he needs to leave you alone first.

Edit: And trust me. I hate upsetting people. I feel like crap when I hurt people or make them sad. I try to let guys down nicely when they ask me out or tell me they like me. But in the case I stated above, that kid was crazy. He texted me so much that I started ignoring him and after a month he sent me a message and I dropped the bomb. "I'M NOT INTO YOU!" xD;