It may be that their parents didn't show them affection?! My background is Italian & German. In my family , they slap the indifference away!
was about 2 say that
They are prideful, brought up in the whole thou-shalt-not-show-emotion-if-thou-wish-to-be-macho.
Depends on how scar-ed they are as children, if you have bad experiences, then affection could be a painful reminder of the past.
You may have to open up first, and show him it's ok to be vulnerable, have a cry, and then show him nothing but love to help heal. Loners usually have very logical minds, and separate themselves from their emotional side. Some repressed trauma, or strong emotional feeling in the past, most likely is the cause.
Affection is fine. It's all the female bull$hit that comes along with it that we can do without.
If you stuck your arm in the knot hole of the tree don't come crying to me when you get bit.
Human Nature is over ridden where broken hearts begin...