hikochan, I have avoided weighing in until now because I wanted to think about this. You have two choices, accept your bf the way he is and try to work with that or go find someone else. I am going to give you advice based on the first scenario.

Try talking to him about what he wants. Get him to tell you about his fantasies. Maybe the reason he is afraid of hurting you is that his fantasies go past where you have told him yours go, and he is actually afraid that he will scare you if he tells you about them.

If he is just afraid of hurting you, perhaps you could set up scenarios where he "rescues" you. You can try some self bondage and make it as painful as you like, and he can some in and help you out of it. After her sees what you can take a few times he might get the idea that you are not as fragile as he thinks.

Try scripting some scenarios. There is a studio in LA that actually does things like this, they have set up different sets and written basic scenarios for them. This is focused mostly on the vanilla crowd that wants some kink in their life, but they actually make some good money at it. The people end up improvising eventually, but at first they are hesitant and stilted.

Another, more drastic solution, is bringing in someone to show him how to do this. There are professional Dom/mes that do this type of thing, and as you are a couple and there will be no sex involved it may even be legal where you live.

These will all take patience on your part, and I must admit that chucking him and finding someone more to your taste might be an easier solution, but I still vote for trying this. I prefer to work within a relationship because they are usually worth it in the end.