In order for him not to get mad at hearing or seeing you, if you ever run into each other again, be polite in greeting him but keep the interaction as brief as possible.
The less time you spend around him, the less likely he will get mad.
Avoid getting into full-fledged conversations with him. Create space between the both of you soon after greeting him briefly.
He needs time to heal from his unresolved emotions. Right now, the bitterness is too poignant.
With time, he may heal. That will allow him to be more clear-headed and less emotional when it comes to you.
At this point, he may no longer have a problem with you.