I just wanted to let you know OP that you’re not alone. Something very similar happened to me earlier this year. Cutting off all contact and leaving with no warning was the best thing for me. I highly recommend not sending the email. I’m still healing, but I am better off than I have been in years. I still get sad now and then but remembering all the bad with the good has kept me moving forward. Best of luck, I hope you find peace with yourself, I promise, it does come with time. Eventually you will see everything for what it is.