Cut contact without hurting his feelings? Impossible, unless he cares nothing for you at all.

I'm sorry, but screw his feelings. He clearly has no regard for your feelings. He lied to you and probably wouldn't hesitate to keep doing it if it kept you around, potentially so you could be his next victim. I fully agree with your friend that ghosting is the best option. What you could do is send him one final IM or something and explain why it's over and then remove him/block him from contacting you before he can respond. That's how I would do it anyways.