How does one go about dealing with an ex that’s in the same class

We sit besides each other and Ofcourse I still care for him we ended in good terms He wasn’t ready for a relationship (months later lol)/had emotional detachment issues/ mental issues. I would saturate him w my affection and apparently became overwhelming for him. I don’t hate him or have resentment towards the fact he lead me on and I’m ok with being friends but I don’t know how I’ll be able to surpass those feelings& keep it cordial. Should I keep my distance and be nice or try to converse with him when he tries to?