1) Because that's what you've been doing since the beginning and it hasn't worked. In fact it pushes him further away.
2) It shows how weak you are and want him to come back out of duty and obligation and not because he likes you.
3) It shows that you haven't changed and that if he were to come back, that you would use fear and guilt to use against him not only in terms of the relationship, but in all other matters as well. For example: "You don't want to eat at that restaurant? That hurts me very much."
4) It breaks one of the primary fundamentals of DBing.
There's more if you want.
By doing that you are cementing their R because you're not making it seem welcome to come home. I mean seriously, who wants to go home to someone who makes them feel guilty all the time?
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.