This question is case by case.( I am a male who has in a committed relation fyi).
1. Specific to your situation I say noway. You obv still have intense feelings for this guy and he can tell u anything if you let him in again you will get hurt and twice as worse as the last time.
To answer the question in general terms I would say the following.
1. Every relationship should hav ea purpose so that it is helping one or both individuals grow. So if one determines that a relationship is non beneficial for the purpose of learning they need to move on. If one can not move on this is the persons ego getting in the way. everyone has a free will and we always have to repect others to make choices that they want to make regardless if that fits into our plan or not. You cant force someone into th emold of what you want them to be or you cant sell yourslef to someone you can never force a relationship. You have to go with the flow but set your boundaries.
2. If a relationship with an ex is something that will not be detrimental to any of the persons invlolved and serves a purpose on some level for growth and respects the boundaries of both other partners than I say that this is a good thing.
best of luck