Would you reject an ex who wanted to be your friend on Facebook and would you message the ex back?

I messaged and put a friend request on Facebook to an ex of mine on Thursday & I show my friend request is still pending on his Facebook. He hasn't messaged me back yet. It has been 10 years since we last spoke & I broke his heart, because he treated me poorly. He pined away for me for eight years. Would you reject the friendship & not message the person back or would you at least show the common courtesy to message the person back if you weren't going to add the ex as your friend on Facebook? I would at least show common courtesy, especially if I were married, I would say that, and then say something like, "Good luck." If I just wasn't interested in renewing a friendship, I would email back at least, and say just that. By the way, I am not married & I have no idea if he is. Thanks.