I can only suggest that you take the advice from someone that has been married and divorced and "healed" from it.
Don't contact him, don't respond to his email, lose his number, leave him alone.
It seems that you
do still have feelings for him because if you didn't you wouldn't have had
any response to his email except a brief laugh. This is a guy that knows how to play games with women's emotions - in my honest opinion - in fact he probably picked that fight with you so that you two could break up, now he's sniffing around again. Bump him.
The best thing you can do is to take care of yourself and move on. I'm not saying it's easy, I'm not saying it won't hurt, but it's a lot better than letting him back into your life.
I put it like this to a girlfriend of mine, when a job fires you, they barely EVER hire you back on. Why? Because they know it's a lost cause, a burnt bridge. You'll be better off if you ignore his email and lose his number. Give yourself closure, don't wait on him.
Lose the 15lbs for yourself, not so that some screw up guy will notice you. Do you, for you.
Don't even worry about him. PM me anytime and I'll tell you how I did it. Let go, move on and never looked back. I did and now I'm happily engaged to the love of my life.