I agree this is normal.
Save the email you sent him. Save but do NOT read future emails.
Save any text messages he sends, again do NOT read. This ALL will come in very handy, should you choose to file 'stalker' charges.
Nothing you can do will change this behavior.
You may want to try some AlAnon and/or some counseling. This can be of great help to ourselves to get through all the 'why' questions.
Also, please keep posting here and let us know how YOU are doing as we do care so very much.
Love and hugs,