Just went thru this (and still am to some degree):
It's normal to still want to be friends, after all you still love him, despite the fact it didn't work for whatever reason. However, you're right. You can't just turn off those feelings. You're priority here is you. Not him. You have to heal from the hurt and disappointment and move on, and if you're anything like me, that will be very hard to do if you still communicate and see your ex. My ex contacted me several times and asked to go to a movie. As much as it hurt to say no, I had to. He just asked me a month or so ago, and we've been broken up for 8 months.
Every relationship is different. I have no idea the dynamics between you two. But based on your post, you still have feelings. Staying in contact and communication will continue to feed those feelings. You can still be 'friends', but set some expectations. Tell him you need time and space and don't expect for you to want to hang out and communicate frequently. He has to find his way, and you have to find yours. You're doing you both a favor by setting this boundary in the post-relationship phase of your 'friendship'.
If it's meant to be for you two to really be genuine friends, it will happen. Could be years down the road, or soon, who knows. In my case, I'm learning that the idea of still wanting to be friends certainly shows you have good intentions. But the fact of the matter is, yeh, we were in a relationship, but we were also friends. Best friends. The relationship was broken and therefore the friendship was broken, and just because you're not in a relationship doesn't mean the friendship part is fixed.
If you both are mature adults and can talk about what went wrong and both take your responsibility for it, then its' possible you both can learn from the experience and mend the friendship. Just don't try to force it right now.
In my case, my ex isn't mature enough. He hasn't taken any responsibility for why it didn't work.