He should be the one feeling guilty and evil for manipulating you. Dump him without an in depth explanation and without entertaining any questions.

He knows you want to break up. You’ve tried multiple times.

He knows WHY you want to break up - you’ve had endless guilt trips and arguments and manipulations, so I’m sure you’ve given him your reasons for wanting to end it.

He has all the information he needs, and at this point he’s proven that he doesn’t deserve a thoughtful discussion and gentle let down because he seizes upon that opportunity to manipulate you.

Break up with a “this isn’t working, and it’s over” statement, physically leave his presence, and block him on everything.