As others have suggested, you are only half of the problem here. Yes, you should probably evaluate whether you're overly critical as a general rule or were overly critical of him. But the fact that he didn't express his feelings and provide you with a meaningful opporunity to change and, instead, chose to just walk out the door suggests to me that he has a lot of work to do on himself, too.
I grew up in a family where the norm was to simply cut people out and walk away, so I understand his approach more than I care to admit. It's taken a lot of work, some therapy, and the love of some very trustworthy people to break that habit.
In any event, I'm very sorry you're hurting.
Hugs,
Kate
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher