That's a good idea. In order not to have false expectations or deceive yourself by hoping for what is not expectable, you have to stop contacting him. You have to avoid any form of friendship - casual and platonic. When you have healed and recovered from the breakup, you can be casual friends but never platonic friends.
My suggestion: You need to sit down with your ex and explain to him. You can head to a coffee shop or someplace (a quiet place). You should let him know that you're trying to heal and recover from the breakup. As of now, you find it hard digesting the fact you're friends while a few days ago you were lovers. Thus, he needs to give you some space so that you can deal with the breakup.
It's better to be open.
You should apologize for what you're going to say before you tell him. This is to avoid causing drama or making things worse.
As far as the two of you are concerned, you are now total strangers. You barely know each other. Therefore, you should only greet each other. Nothing more. You have to let him know about this. Also, no discussing the project or any subject/topic the two of you. The discussion should involve more than the two of you.
You can study in the same class but no more chatting or discussing together. The discussions should involve others.
Be friendly. Let not your face betray your heart. Forgive him and yourself. Don't hold any bitterness or hatred. Only greet each other. Unless you're in the same group, don't talk more than basic greetings.