Don’t overthink it or get yourself emotional about it. Just state facts (observable, measurable, non editorialized facts) and how those facts have affected you. Then stop there. Don’t prescribe solutions or actions he should take. Don’t threaten to do something. Just say what’s happening and the effect it’s had on you.

Feedback like this is an amazing gift and he’ll appreciate you for it.

Then give it time and if things don’t get better, you have your answer and you need to control what you can control. Either accept it or move on.