Any person who is actively cheating (lying, deceiving, secretive etc.) be it micro or any other definition on you, is not loving you.
A person who truly loves you would not behave in such a manner towards you. Ever. A person who is a real friend would never do that to you either. He was secretly dishonest with you.
You did well by asking him to leave. That took courage. You broke up with him. That took resilience.
You say you are invested in his journey and development. This attachment you have for him is playing you. You are not his therapist, you are not his friend. He cheated on you in all secrecy. Invest in yourself and your development away from this situation.
Heal yourself first. Your question should be what have I learnt about myself from this experience instead of asking yourself about keeping a friendship..
I wish you the best in moving on.