First of all why this misundestanding happened. Is it too serious that he has dumped you? Have you tried to resolve this issue? I am asking this because I don’t know the actual reason and severty of misunderstanding. In a relationship this happened sometime. If your boyfriend is not contacting you then you should take initiative. Talk to him and solve all misunderstanding. Later on you will have satisfaction that you have tried your level best.
Second thing is that you should not take any step in hurry. Your new friend behaviour seems suspitious to me. When we are in pain and looking for someone then we come close to any person easily and without thinking and got cheated. If he is your friend and well wisher then he should not be physical with you. Avoid that as of now. He may move further and try to do something more with you. So beware with this. I have seen lot many boys who become more caring and loving initially. Later after making physical relation they start ignoring. If this happen with you then you will feel much more guilty later, which will more painfull for you.
First try to solve your problem with your old friend. If possible. But you should give a try.
If he still ignore you than wait for sometime then move further. Use your brain also in new relationship and avoid cheating risk. If later own you agree to proceed further with this friend then clear all the things.
Be happy. Life is very precious live every moment. Search happyness and spread happyness.