Straight to advice
Anonymous 1: Something is missing from your friend's side of problem. We don't really know if he never entered a relationship or he have, but so far has not really felt been in love.
If it happens to be the first case : then I advise he spend much time with a girl through communication. The chemistry rapport will build up from there.
And if it's the second : he don't need any advice. Love will find it place in his heart someday. I have friends who were like that at one time
Anonymous 2 : Believe me , your ex wishes you well and you probably might have a good relationship with her friend but it's a risk. Why did I say so? In the future, she might abuse your now present wife who happened to be her friend in the name of "she made her courtship with you possible through her" or you may not fully forget her which may lead to cheating your wife with your ex"